Gm Pd-4107 User manual

MAINTENANCE

MANUAL

GM

GENERAL

MOTORS

CORPORATION

C01\CIIES

COACH MODEL

PD-4107

X-6614

INDEX

Front

Axle

Rear

Axle

Body

Brakes

Clutch

Cooling

Electrical

Engine

Fuel

------------------------•

Lubrication

GMC TRUCK & COACH

DIVISION

GENERAL MOTORS CORPORATION

Pontiac, Michigan

55020

COACH INFORMATION NETWORK

Air -

Suspension A

--

Steering

-

------

Transmission

Propeller

Shaft

------

a

www.coachinfo.com Hubs,

Wheels,"!!al

_______

and

Tires

~

©

1

966

GENERAL MOTORS

CORPORATION

GMC

TRUCK

&

COACH

DIVISION

X-6614

3M

1

-66

Printed

in

U.S.A.

Air

~

Conditioning

~

NOTICE:

THIS

IS

A PHOTOCOPY

REPRODUCTION OF A

PUBLICATION THAT

IS

OUT OF PRINT.

THEREFORE SOME

DEGRADATION OF COPY

IS

TO BE EXPECTED.

INTRODUCTION

This

manual

contains

complete

service,

maintenance,

and

repair

information

on

GM

Inter-City

Coach

Model

PD-4107.

Information

in

this

manual

pertains

to

standard

equipment

and

the

most

commonly

used

special

equipment.

Operation

of

the

vehicle

from

the

standpoint

of

the

driver

is

contained

in

a

separate

Operating

Manual.

For

information

on

the

Diesel

Engine,

refer

to

the

current

Diesel

Engine

Maintenance

Manual.

Every

effort

has

been

made

to

include

timely

and

adequate

information

on

the

various

units

and

systems

used

on

the

PD-4107

Coach.

The

maintenance

and

repair

procedures

in

the

various

manual

sections

are

the

result

of

extensive

service

experience.

This

information

should

serve

not

only

as

a

reference

for

the

experienced

mechanical

force,

but

also

as

a

comprehensive

text

for

training

purposes.

All

information

contained

in

this

manual

is

based

on

the

latest

product

information

available

at

the

time

of

publication

approval.

GMC

Truck

and

Coach

Division

reserves

the

right

to

make

product

changes

at

any

time.

GENERAL

INFORMATION

ABOUT THIS

MANUAL

ARRANGEMENT

This

manual

is

divided

into

major

sections

in

the

sequence

shown

on

the

margin

of

the

title

page. A

black

tab

bearing

the

major

section

number

is

placed

on

the

first

page

of

each

major

section

which

indexes

with

the tab

on

the

title

page.

Many

of

the

major

sections

are

divided

into

sub-sections,

each

sub-section

containing

important

and

specific

information

on

or

components.

When

a

major

section

is

divided

into

sub-sections,

a

section

index

appears on

the

first

page

of

the

major

section.

PAGE AND

ILLUSTRATION

NUMBERS

The

manual

pages

are

numbered

consecutively

throughout

the

manual.

Illustrations

are

num-

bered

consecutively

within

each

section,

or

within

each

sub-section

when

the

major

section

is so

divided.

SPECIFICATIONS

Service

data,

fits,

and

tolerances

are

listed

at

the

end

of

most

sections

or

sub-sections

under

the

heading

"Specifications."

Manufacturers

model

or

part

numbers

are

used

in

many

instances

in

the

"Specifications"

tabulation.

These

numbers

are

provided

primarily

for

unit

identification

and

should

be

referred

to

when

ordering

parts.

All

detail

service

part

numbers

must

be

obtained

from

the

applicable

Parts

Book.

SPECIAL

TOOLS

Special

tools

and

equipment

are

mentioned,

and

in

many

instances

illustrated,

throughout

the

text.

These

tools

are

specially

designed

to

accomplish

certain

operations

efficiently

and

readily.

Such

tools

are

identified

in

the

text

by

tool

vendor's

numbers.

These

tools

are

not

offered

for

sale

by

GMC

Truck

and

Coach

Division.

Information

regarding

availability

of

these

tools

can

be

obtained

from

your

GM

Coach

Service

Representative

or

from

the

Factory.

SERVICE BULLETINS

Service

bulletins

are

issued,

when

required,

supplementing

or

in

some

cases

superseding

infor-

mation

in

this

manual.

Information

in

these

bulletins

should

be

noted

in

the

text

and

the

bulletin

filed

for

ready

reference.

ALPHABETICAL

INDEX

Important

subjects,

with

manual

page

number

references,

are

alphabetically

listed

at

the

end

of

this

manual.

Page

iii

GENERAL DATA

The

data

listed

below

includes

only

general

information

on

the

PD-4107

Coach.

For

specific

data

and

specifications,

refer

to "Specifications"

at

end

of

each

section

or

sub-section.

MODEL

DATA

Length

(overall)

.....................................................

35

ft.

Width

(

overall)

....................................................

95¾

in.

Height

(maximum)

...............................................

1311h in.

Wheelbase

.........................................................

261

in.

Track

Front

...........................................................

79¼

in,

Rear

(center

of

dual

tires)

.......................................

701/2

in.

Turning

Radius

Wheels

(

right

and

left)

.............................................

39

ft.

Body

Corner

(

right

and

left)

.......................................

.43 ft.

Tire

Size

(standard)

.............................................

12.00/22.5

Fuel

Tank

Capacity

......................................

Standard-140

gal.

Optional-165

gal.

Cooling

System

Capacity

(including

heating

system)

.................

92

qts.

ENGINE

DATA

Engine

Model

.....................................................

8V

-71N

Displacement

..................................................

567.5 cu. in.

Bore

and

Stroke

..............................................

4¼

in. x 5 in.

Compression

Ratio

..................................................

18.7

:1

Brake

Horsepower

at

Governed

Speed

(1800

rpm)

......................

252

SERIAL NUMBER

LOCATIONS

Delay

and

confusion

can

be

avoided

when

correct

serial

numbers

of

vehicle

and

engine

are

placed

on

parts

orders

and

correspondence.

Locations

of

these

serial

numbers

are

illustrated

below.

GM

G(N[Rll

MOTORS

1

i•Xiiii

BUILT

BY

GMC.

TRUCK

ii

COAC.H

DIVISION

GENERAL

MOTORS

CORPORATION

PONTIAC..

MIC.H.

U.

5 A

TYPE

COACH

NO

PLATE

ON

RIGHT

SIDE

OF DASH

*8VA

1887

7087

4220

RIGHT

SIDE

OF CYLINDER

BLOCK

ON

BULKHEAD

IN

TOOL COMPARTMENT

Page

iv

GM

COACH

MAINTENANCE

MANUAL

Sec.

1

Page 1

This

group

is

divided

into

two

sections

covering

"FRONT

END ALIGNMENT" and

"FRONT

AXLE REPAIR."

Proper

front

end

alignment

must

be

maintained

to

insure

ease

of

steering

and

satisfactory

tire

life.

Front

end

alignment

inspections

generally

fall

into

two

groups:

(1)

Regular

service

inspections

performed

at

periodic

intervals,

and (2)

Inspections

to

determine

extent

of

damage

after

a

collision

or

severe

service.

Regular

service

inspections

are

primarily

concerned

with

toe-in,

camber,

and

caster.

With

proper

equipment

these

specifications

are

easily

checked.

Any

variation

from

these

specifications

will

indicate:

(1)

need

for

adjustment,

or

(2)

more

thorough

inspection

to

determine

if any

steering

or

front

axle

parts

are

bent

and

require

replacement.

Complete

front

end

alignment

data

is

given

under

"Front

End

Alignment

Data"

at

end

of

this

section.

DEFINITION

OF

TERMS

WHEEL

TOE-IN.

Distance

front

wheels

are

closer

together

at

front

than

at

rear

of

axle

(see

"G"

minus

"H,"

fig. 1).

WHEEL CAMBER. Amount

wheels

are

inclined

from

vertical

plane

(see

"C,"

fig. 1).

FRONT AXLE CASTER.

Inclination

of

king

from

the

vertical

in

the

fore

and

aft

direction

of

the

vehicle

(see

"X,"

fig.

1).

KING PIN INCLINATION.

The

slant

of

the

king

toward

the

center

of

the

vehicle

at

the

top and

out-

ward

at

the

bottom

(see

"D,"

fig. 1).

STEERING GEOMETRY.

The

design

of

the

front

end

which

causes

the

front

wheels

to

stay

in

proper

relative

alignment

when

the

wheels

are

turned

to

right

or

left.

FRONT END INSPECTION

Before

checking

front

end

alignment,

the

fol-

lowing

front

end

inspection

should

always

be

made:

1.

Check

tires

for

proper

inflation.

2.

Check

wheel

installation

and

run-out.

3.

Check

wheel

bearing

adjustment.

4.

Check

tie

rod

and

drag

link

ends

for

loose-

ness.

5.

Check

king

pins

for

looseness.

Front

end

alignment

requires

the

vehicle

to

be

level

while

being

checked.

Full

weight

must

be

on

wheels

with

vehicle

empty.

ALIGNMENT

FRONT WHEEL

TOE-IN

Toe-in

is

measured

from

centers

of

tire

tread.

Measurements

at

both

front

and

rear

of

axle

(see

"H"

and

"G,"

fig.

1)

must

be

made

at

same

height

from

floor.

First

hoist

front

of

vehicle

and

spin

wheels

to

obtain a

center

line

on

tire

treads.

Place

wheels

in

straight-ahead

position.

Roll

the

vehicle

straight

ahead

for

several

feet

to

where

the

inspection

is

to

be

made.

This

will

remove

any

slack

caused

by

looseness

in

the

wheel

bearings

or

steering

connections.

Measure

at

point

"H"

-and

"G"

(fig. 1).

Toe-in

is

"G"

minus

"H."

Incorrect

toe-in

results

in

excessive

tire

wear

caused

by

side

slippage.

Unstable

steering

with a

tendency

to

wander

may

also

result.

Toe-in

Adjustment

NOTE: If

toe-in

has

to

be

changed

a

consider-

able

amount,

drag

link

must

be

removed,

then

re-

installed

and

readjusted

so

steering

gear

will

not

be

thrown

off high

point.

1.

Loosen

clamp

bolts

which

retain

each

tie

rod

end

on

tie

rod.

2.

Using

a

pipe

wrench,

turn

tie

rod

tube

as

required

to

obtain

correct

toe-in

measurement.

3.

After

correct

adjustment

is

obtained,

make

certain

that

both

tie

rod

ends

are

in

the

same

plane;

then

tighten

all

clamp

bolts

firmly.

4.

Recheck

toe-in

to

make

sure

adjustment

was

not

changed

when

clamp

bolts

were

tightened.

FRONT WHEEL CAMIIER

Positive

Camber

is

outward

inclination

of

wheels

at

top;

Negative

or

Reverse

Camber

is

in-

ward

inclination

of

wheels

at

top.

This

vehicle

is

designed

with

positive

camber.

Camber

variations

may

be

caused

by

wear

at

wheel

bearings

and

Sec.

1

Page

2

GM

COACH

MAINTENANCE MANUAL

FRONT

END

ALIGNMENT

B

MINUS A

C

.....

.

D

.....

.

E

G MINUS H

J

.....

.

M

.....

.

N

(MECH.)

N (POWER)

H

------+------1

Centerline

of

axle

is

marked

by

4 prick

--

-

---

punch

marks

on

rear

face

of

axle

-

With

Power

Steering

TOE-IN,

ROD

AND ARM LOCATIONS

~

H

_

Centerline

of

axle

is

marked

by

4 prick

-1-

punch marks on

rear

face

of

axle

I

j

i

I

With Mechanical Steering

TOE-IN,

ROD

AND ARM LOCATIONS

Camber

(Inches)

Camber

(Degrees)

King Pin

fnclination

(Degrees)

Top of

Tie

Rod

Tube

Below Top

of Axle

Front

Wheel

Toe-in

(Inches)

Centerline

of

Tie

Rod

End

Stud

to

Wheel

Rim

Centerline

of Axle

to

Center

of

Tie

Rod

End

Studs

Centerline

of Axle

to

Center

of

Steering

Arm

End

(At

Drag

Link)

Centerline

of Axle

to

Center

of

Extension

End

Stud

CAMBER,

PIN INCLINATIONS,

AND

ROD

LOCATIONS

~

Front-

FRONT

AXLE

CASTER

KING PIN INCLINATION

CASTER

P . . . . . . Bottom of

Tie

Rod

Arm

Boss

to

Top

of Axle Beam

S MINUS T

U MINUS

V

X

y

z

Caster

(Inches)

(Measure

at

Front

of Axle)

King Pin

Inclination

(Inches)

Caster

(Degrees)

Vertical

Centerline

of King Pin

T-2200-1

Figure

1-Front

End

Alignment

Chart

GM

COACH

MAINTENANCE MANUAL

Sec.

1

Page 3

steering

knuckle

bushings,

or

by

bent

steering

knuckle

or

sagging

axle

center.

In

checking

camber

it

is

recommended

that

an

accurate

gauge

be

used.

If

a

camber

gauge

is

not

available,

readings

can

be

taken

as

illustrated

at

"A"

and

"B" on

chart

(fig. 1).

Place

square

as

shown

and

measure

distance

between

"A"

and

rim,

and

"B"

and

rim.

Lower

dimension

should

exceed

upper

dimension

by

amount

listed

in

"Front

End

Alignment

Data"

at

end

of

this

section.

This

dimen-

sion

on

right

wheel

should

not

vary

over

3/

32"

from

same

dimension

taken

at

left

wheel.

If

final

camber

reading

is

incorrect,

either

steering

knuckle

or

axle

center

is

bent.

To

deter-

mine

which

part

is

bent,

check

king

inclination

("D,

11

fig.

1).

Camber

plus

king

inclination

is

the

INCLUDED ANGLE of

steering

knuckle.

If

in-

cluded

angle

of

knuckle

varies

more

than

1/2

de-

gree

from

values

given

in

"Front

End

Alignment

Data,"

knuckle

is

bent.

Excessive

positive

camber

results

in

irregular

wear

of

tires

at

outer

shoulders.

Negative

or

re-

verse

camber

causes

wear

at

inner

shoulders.

Ease

of

steering

is

affected

by any

deviation

from

specified

camber.

AXLE

CASTER

Positive

Caster

is

the

inclination

of

the

king

pins

toward

rear

of

vehicle.

Negative

or

Reverse

Caster

is

the

inclination

of king

pins

toward

front

of

vehicle.

This

vehicle

is

designed

with

positive

caster.

Caster

variations

may

be

caused

by

bent

axle,

or

tilting

of

side

suspension

supports.

Precision

instruments

must

be

used

to

check

caster

angles

when

axle

is

installed

in

vehicle.

Caster

can

be

adjusted

on

vehicle

by

loosening

clamp

bolts

in

adjusting

clamp

(fig.

2)

and

turning

clamp.

Adjust

to

dimension

listed

in

"Front

End

Alignment

Data"

on

Tighten

clamp

bolts

firmly

after

adjustment.

When

axle

is

removed

from

vehicle,

check

can

be

made

on

bench

as

follows:

Place

two

uniform

blocks

on

level

surface.

Rest

suspension

support

seats

on

blocks.

Using

square,

measure

"S"

and

"T"

dimensions

(fig.

1)

at

front

side

of

axle.

"S"

minus

"T"

equals

caster

in

inches.

If

this

dimension

does

not

agree

with

specified

value,

the

axle

is

twisted.

The

purpose

of

caster

is

to

provide

steering

stability

by

keeping

the

wheels

in

a

straight-ahead

position.

Variations

from

specified

caster

values

will

affect

steering

stability

causing

wandering,

difficulty

in

pulling

out

of

curves,

and a

tendency

toward

wheel

shimmy.

FRONT

END

ALIGNMENT

Figure

2-Caster

Adjusting

Clamp

KING PIN

INCLINATION

Precision

instruments

must

be

used

to

check

king

inclination

when

axle

is

installed

in

vehicle.

When

axle

is

removed,

check

can

be

made

on

bench

as

follows:

Place

two

uniform

blocks

on

level

surface,

rest

suspension

support

seats

on

blocks.

Using

square,

measure

"U"

and

"V"

dimensions

(fig. 1).

"U"

minus

"V"

equals

king

inclination

in

inches.

If

axle

is

bent

or

twisted,

axle

center

must

be

replaced.

STEERING

GEOMETRY

(Refer

to

Fig.

1)

Since

the

angularity

of

the

steering

arms

largely

controls

steering

geometry,

checking

the

alignment

of

the

steering

arms

and

linkage

is

an

important

alignment

factor.

After

making

all

other

front

end

alignment

checks,

inspect

steering

arms

for

proper

install-

ation,

then

measure

steering

arm

angles

as

follows:

1.

Position

of

top

of

tie

rod

tube

below

top

of

axle

("E").

2.

Distance

of

center

of

tie

rod

end

studs

to

edge

of

wheel

rims

("J").

3.

Distances

of

center

of

tie

rod

end

studs

to

centerline

of

axle

("M").

4.

Distance

from

centerline

of

axle

to

center

of

steering

arm

end

(at

drag

link) ("N") (Mech.

Steering).

5.

Distance

from

centerline

of

axle

to

center

of

extension

end

stud

(at

steering

arm)

(N")

(Power

Steering).

If

these

dimensions

are

not

within

specified

values,

the

steering

arms

or

steering

linkage

are

bent

and

should

be

replaced.

Refer

to

for

"Front

End

Alignment

Data."

Sec.

1

Page

4

GM

COACH

MAINTENANCE MANUAL

FRONT

AXLE

REPAIR

POINTS

ON

CHART

B

MINUS

A

C

D

E

G

MINUS

H

J

M

N

(MECH.)

N

(POWER)

p

S

MINUS

T

(MECH.)

S

MINUS

T

(POWER)

U

MINUS

V

X

(MECH.)

X

(POWER)

1 King

Nut

FRONT END ALIGNMENT DATA

(Refer

To

Front

End

Alignment

Chart, Figure 1)

Wheel

Camber

(Inches)

Wheel

Camber

(Degrees)

King

Inclination

(Degrees)

Top

of

Tie

Rod

Tube

Below

Top

of

Axle

(Inches)

Front

Wheel

Toe-in

(Inches)

DIMENSIONS

1½2

1

8

5½

plus

or

minus½

Oto

½G

Centerline

of

Tie

Rod

End

Stud

to

Wheel

Rim

(Inches)

*Centerline

of

Axle

to

Center

of

Tie

Rod

End

Studs

(Inches)

2

1

5/22

32½2

3l2½2

32%

*Centerline

of

Axle

to

Center

of

Steering

Arm

End

(At

Drag

Link)

(Inches)

*Centerline

of

Axle

to

Center

of

Extension

End

Stud

(Inches)

Bottom

of

Tie

Rod

Arm

Boss

to

Top

of

Axle

Beam

(Inches)

Caster

(Inches)

(Measured

at

Front

of

Axle)

5

%

o/J.6

l½

l½-2

3

Caster

(Inches)

(Measured

at

Front

of

Axle)

.

King

Inclination

(Inches)

Caster

(Degrees)

Caster

(Degrees)

Front

Wheel

Track

at

Ground

(Inches)

79¼

*Centerline

of

Axle

is

Prick-punched

on

Face

of

Axle

Beam

7

Expansion

Plug

CONSTRUCTION

Front

axle

assembly

is

Reverse

Elliott

type.

Axles

are

equipped

with

steering

knuckles

con-

structed

as

shown

in

figure

1.

Wheel

bearings,

air

suspension,

steering

gear

housing,

and

brake

parts

which

are

mounted

on

front

axle

are

described

in

their

respective

sec-

tions

in

this

manual.

Specifications

and

pertinent

front

axle

service

information

are

given

in

"Specifications"

at

end

of

this

section.

2

King Pin Cover 8

Steering

Knuckle

Bushing

Front

axle

assembly

center

section

is

a hollow

rectangular

tube

in

which

dowel

pins

are

installed

to

locate

air

suspension

supports.

Outer

ends

of

axle

are

solid

forgings

machined

to

accommodate

steering

knuckles

and

king

pins.

3

King

Bushing

4

Spacing Washer

5 Axle Center End

6

King

9

Thrust

Bearing

Assembly

10

Steering

Knuckle

TP-6335-1

Figure

1-Steering

Knuckle

Assembly

Steering

knuckles

(fig. 1)

are

supported

on

solid

king

pins

which

are

tapered

at

center

section

to

fit

snugly

in

tapered

holes

in

axle

outer

ends.

Nut

installed

at

threaded

upper

end

of

each

king

locks

king

bushing

(3,

fig.

1)

against

washer

(4,

fig.

1)

and

secures

king

in

axle.

King pin

nuts

are

secured

by

cotter

pins.

GM

COACH

MAINTENANCE MANUAL

Sec.

1

Page 5

Load

is

transmitted

from

axle

center

to

steer-

ing

knuckles

through

tapered

roller

thrust

bearing

assemblies

(9,

fig.

1).

Covers

and

plugs

(2

and

7,

fig.

1)

exclude

dust

and

moisture

from

knuckle

bushings

and

serve

as

lubricant

seals.

Steering

knuckle

bushings

can

be

replaced

when

necessary.

Stop

screws

installed

at

each

end

of

axle

center

limit

turning

angle

of

front

wheels.

FRONT

AXLE

GENERAL

MAINTENANCE

INSPECTION

Following

inspection

operations

should

be

per-

formed

at

intervals

determined

by

severity

of

service.

1.

Inspect

air

suspension

support

stud

nuts

and

U-bolt

nuts.

Tighten

as

directed

in

AIR SUS-

PENSI0N (SEC. 14).

2.

Inspect

and

tighten

tie

rod

arm

and

steer-

ing

arm

nuts.

Torque

specifications

are

shown

in

"Specifications"

at

end

of

this

section.

3.

Inspect

steering

arm

and

tie

rod

arm

nuts

for

looseness.

Tighten

if

necessary.

Also

inspect

tie

rod

end

stud

nuts

for

looseness

and

check

tie

rod

ends

for

wear.

4. When

steering

difficulty

or

abnormal

tire

wear

indicate

necessity,

check

front

end

alignment

as

previously

instructed

under

"FRONT

END

ALIGNMENT."

5.

Check

stop

screws

and

adjust

when

nec-

essary.

Stop

screw

adjustment

procedure

is

des-

cribed

later.

6.

Lubricate

front

axle

parts

as

instructed

in

LUBRICATION (SEC. 13).

7. When

lubricating

front

axle

parts,

observe

condition

of

seals

at

steering

knuckle,

tie

rod

ends,

and

drag

link.

If

seals

are

found

to

be

damaged

or

missing,

new

seals

should

be

installed

immediately.

8.

Periodic

inspection

should

be

made

at

steering

knuckles

to

determine

if

excessive

up-

and-down

movement

of

knuckles

on

king

pins

exists.

Since

excessive

pounding

will

damage

thrust

bear-

ing

(9,

fig.

1),

the

up-and-down

movement

of

steer-

FRONT

AXLE

REPAIR

ing

knuckles

must

be

kept

within

prescribed

limits.

Shims

for

use

in

reducing

clearance

are

available.

STOP SCREW ADJUSTMENT

Stop

screws,

installed

in

front

axle

center,

limit

front

wheel

turning

angle

to

right

and

left.

Stop

screws

must

be

set

properly

to

give

equal

turning

radius

to

the

right

and

to

left,

as

well

as

to

limit

turning

angle

and

thereby

prevent

interfer-

ence

between

front

tires

and

other

parts

of

coach.

Before

setting

stop

screws,

refer

to

STEER-

ING

GEAR

(SEC. 16)

and

be

sure

Pitman

arm

is

properly

installed

on

steering

gear,

and

be

sure

steering

gear

drag

link

is

properly

adjusted

for

length.

Also,

make

sure

air

suspension

is

pressur-

ized.

Adjust

stop

screws

as

follows:

1.

Raise

front

axle

until

front

wheels

are

off

floor.

2.

Turn

front

wheels

to

extreme

left,

measure

and

record

distance

from

left

front

tire

to

nearest

point

on

coach.

In

this

position

there

should

be

a

3/

4

to

1-inch

clearance.

3.

If

not

within

3/

4

to

1-inch,

turn

stop

screw

in

or

out

until

proper

clearance

is

obtained.

Secure

stop

screw

setting

with

lock

nut, and

recheck

to

make

sure

dimension

was

not

changed

when

lock

nut

was

tightened.

4.

Turn

wheels

to

extreme

right

position

and

repeat

procedure

mentioned

above

at

right

front

tire.

If

this

dimension

is

not

same

as

the

corres-

ponding

dimension

at

left-hand

side

of

coach,

ad-

just

right

stop

screw

to

provide

same

dimension.

5. When

adjustment

is

completed,

road

test

coach

and

note

if any

interference

takes

place

be-

tween

tires

and

other

parts

of

coach

while

making

sharp

turns

in

either

direction.

FRONT

AXLE

REPLACEMENT

Refer

to

AIR SUSPENSION (SEC. 14)

for

pro-

cedures

necessary

to

remove

and

install

front

axle

assembly.

FRONT

AXLE

OVERHAUL

Steering

knuckles,

king

pins,

and

bushings

may

be

replaced

without

removing

front

axle

as-

sembly

from

vehicle.

However,

when

front

axle

assembly

requires

a

complete

overhaul,

the

as-

sembly

may

be

removed.

Certain

preliminary

inspections

can

be

made,

while

axle

is

still

mounted

on

vehicle,

which

will

aid

in

determining

the

amount

of

repair

work

nec-

essary.

Check

front

end

alignment

as

previously

directed

in

"FRONT

END ALIGNMENT"

section.

Inability

to

align

front

end

correctly

indicates

that

axle

center

or

steering

knuckle

is

distorted,

steer-

ing

arms

are

bent,

or

bushings

in

steering

knuckle

yokes

are

worn

beyond

limits.

Repair

procedures

on

such

items

as

brakes,

wheel

bearings,

and

steering

gear

are

covered

in

respective

sections

of

this

manual.

STEERING

KNUCKLE

REMOVAL

If

desired,

steering

knuckles

may

be

removed

from

front

axle

without

removing

front

axle

as-

sembly

from

the

vehicle.

To

remove

steering

Sec.

1

Page 6

GM

COACH

MAINTENANCE MANUAL

FRONT AXLE

REPAIR

knuckles

from

the

axle

either

with

or

without

re-

moving

the

front

axle

assembly

from

vehicle,

proceed

as

follows:

1.

Remove

cotter

pins

and

nuts

from

tie

rod

end

studs,

then

using

a

soft

plastic

hammer,

tap

studs

until

tie

rod

is

loose;

remove

tie

rod.

2.

On

vehicles

equipped

with

mechanical

steer-

ing,

remove

drag

link

from

steering

arm.

On

ve-

hicles

equipped

with

power

steering,

remove

ex-

tension

and

end

socket

assembly

from

steering

arm

as

directed

in

STEERING

(SEC. 16) of

this

manual.

3.

Remove

front

wheels,

hubs,

and

bearings.

Refer

to

HUBS,

WHEELS, AND

TIRES

(SEC. 19).

4.

Remove

air

brake

mechanism

and

brake

shoes.

Detach

brake

shoe

spider

from

knuckle

and

remove

spider,

camshaft,

and

slack

adjuster

as

an

assembly.

5.

Remove

nuts

from

steering

tie

rod

arms

and

drive

arms

out

of

steering

knuckles.

6.

Remove

cover

(2,

fig.

1)

from

top of

knuckle

to

expose

king

nut.

Remove

snap

ring

from

knuckle

lower

yoke

and

remove

expansion

plug.

7.

Remove

cotter

pin,

then

remove

nut

from

upper

end

of king

pin.

Using

suitable

brass

drift,

drive

king

downward

out of

axle

and

knuckle.

Remove

knuckle,

thrust

bearing,

and

spacing

wash-

er

from

axle.

King

bushing

can

be

lifted

out

of

knuckle

upper

yoke.

CLEANING

Wash

steering

knuckle

parts

in

cleaning

solu-

tion,

being

sure

to

remove

all

dirt

and

lubricant.

If

necessary,

soak

thrust

bearings

in

cleaner

until

all

old

lubricant

is

dissolved;

then

slush

bearing

in

cleaning

solution

until

all

grit

is

removed

from

races.

INSPECTION

AND

REPAIR

STEERING

KNUCKLES

After

steering

knuckles

have

been

cleaned,

thoroughly

examine

knuckles

for

distortion,

dam-

age,

cracks,

or

fractures.

If

Magna-Flux

inspec-

tion

equipment

is

available,

use

this

method

to

in-

spect

steering

knuckles

and

king

pins

for

minute

cracks,

checks,

or

fractures

which

otherwise

would

not

be

visible

to

the

naked

eye.

AXLE

CENTER

There

are

two

conditions

which, if

either

exists,

will

necessitate

replacement

of

axle

center.

1.

If

king

holes

in

axle

center

ends

are

worn

to

such

an

extent

that

a

new

fits

loosely,

axle

center

must

be

replaced.

2.

If

axle

center

has

been

twisted

or

bent

more

than

5

degrees

from

original

shape,

the

cen-

ter

should

be

replaced.

When

an

extreme

bent

condition

exists,

minute

invisible

fractures

may

occur

and

cause

failure

under

ordinary

operating

conditions.

Checking

Axle

Center

Check

axle

center

for

twist

with

alignment

instruments,

or

on a

bench

as

illustrated

in

front

end

alignment

chart

(fig. 1

in

"FRONT

END ALIGN-

MENT"

section).

If

equipment

is

available,

use

Magna-Flux

method

to

check

axle

center

for

min-

ute

fractures.

THRUST BEARINGS

Examine

thrust

bearings

for

excessive

wear,

pitting,

or

other

damage.

If

these

conditions

are

evident

or

if

bearing

retainers

are

bent

or

damag-

ed,

bearings

should

be

replaced.

BUSHING

REPLACEMENT

Steering

knuckle

bushings

should

be

replaced

if

inspection

reveals

that

they

are

scored,

worn,

or

otherwise

damaged.

Removal

1.

Clamp

steering

knuckle

securely

in

vise

equipped

with

soft

jaws.

2.

Thread

tap

of

suitable

size

into

bushing,

if

bushing

driver

is

not

available.

3.

Using

soft

metal

rod,

slightly

smaller

than

bushing

and

long

enough

to

extend

at

least

1-1/2"

through

opposite

knuckle

yoke,

drive

tap

and

bush-

ing

out

of

knuckle

bore.

4.

Repeat

process

to

remove

remaining

steer-

ing

knuckle

bushing.

Installation

1.

Clean

the

steering

knuckle

bushing

bores,

then

round

off

all

sharp

edges

of

new

bushings

slightly.

2.

Position

bushing

so

that

oil

hole

in

bushing

will

line

up

with

lubrication

fitting

hole

in

steering

knuckle

yoke,

and

so

that

bushing

will

enter

knuckle

bore

straight

when

pressed

into

yoke.

3.

Using

arbor

press

and

suitable

installer,

press

bushing

(8,

fig.

1)

into

knuckle

bore

until

positioned

as

shown

in

figure

1.

NEVERATTEMPT

TO

DRIVE

BUSHINGS WITH HAMMER.

4.

Ream

or

hone

bushings

to

diameter

given

in

"Specifications"

at

end

of

this

section.

5.

Clean

cuttings

out of

oil

grooves,

then

round

off

all

sharp

edges

in

grooves.

KING PIN

Check

diameter

of

king

at

upper

and

lower

bearing

surfaces

against

dimensions

given

in

"Specifications"

at

end

of

this

section.

If

wear

ex-

ceeds

limits

given,

replace

with

new

king

pin.

King

pins

should

also

be

inspected

for

minute

cracks

or

other

damage.

GM

COACH

MAINTENANCE

MANUAL

Sec.

1

Page 7

STEERING

KNUCKLE

INSTALLATION

The

importance

of

cleanliness

when

assem-

bling

steering

knuckle

parts

cannot

be

overstress-

ed.

If

the

king

pins

and

bushings

are

installed

with

particles

of

dirt

or

metal

between

bearing

sur-

faces,

excessive

wear

will

result

necessitating

premature

replacement

of

parts.

Install

steering

knuckles

and

king

pins

in

the

following

manner.

Key

numbers

in

text

refer

to

figure

1.

Position

steering

knuckle

(10) on

axle

cen-

ter

end

(5),

then

slide

thrust

bearing

assembly

(9)

into

place

between

lower

face

of

axle

center

and

steering

knuckle

lower

yoke.

Make

sure

retainer

is

on

top

of

bearing

with

lip

of

retainer

down.

Align king

holes

in

steering

knuckle

yokes

with

king

hole

in

axle

center

end.

2.

With

axle

center

held

rigidly,

place

a

jack

under

knuckle

yoke

and

raise

knuckle

sufficiently

to

take

up

all

clearance

between

lower

yoke,

thrust

bearing,

and

lower

face

of

axle

center

end.

3.

Check

clearance

between

top

face

of

axle

center

end

and

lower

face

of

steering

knuckle

yoke,

then

select

shim

and

spacing

washer

(4)

combin-

ation

which

will

reduce

clearance

to

limits

given

in

"Specifications"

at

end

of

this

section.

Shim

and

spacing

washer

thicknesses

available

are

given

in

"Specifications"

at

end

of

this

section.

4. Make

certain

king

hole

in

axle

center

(5), king

(6),

and

nut

(1)

are

carefully

cleaned

and

dry.

King

nut

(1)

should

screw

on

king

freely

without

binding

in

any

manner.

These

pre-

cautions

should

be

taken

to

assure

king

being

securely

locked

in

place

when

installation

is

com-

pleted.

5.

Insert

king

(6)

through

bottom

yoke

of

steering

knuckle

(10),

then

drive

king

into

place

with

lead

hammer.

6.

Place

king

bushing

(3)

over

threaded

end

of king

(6),

then

press

bushing

into

place.

Be

sure

king

bushing

is

installed

squarely

on

king

pin.

7.

Make

sure

threads

on king

nut

are

clean

and

dry,

then

install

king

nut

(1).

Tighten

nut

with

torque

wrench

to

minimum

torque

given

in

"Specifications"

at

end

of

this

section,

then

tighten

nut

until

on

nut

lines

up

with

cotter

hole

through

king

pin.

Install

new

cotter

pin,

full

size

of

cotter

hole.

8.

Position

new

cover

gasket

on

steering

knuckle

upper

yoke,

place

cover

(2) on

gasket,

then

secure

cover

with

attaching

screws.

9.

Install

new

plug

(7)

in

lower

yoke,

then

in-

stall

snap

ring

to

retain

plug.

Install

plug

with

con-

cave

side

toward

snap

ring

so

edge

of

plug

contacts

ring.

10.

Place

keys

in

keyways

in

tie

rod

arms

and

steering

arm

and

drive

arms

into

tapered

holes

in

FRONT

AXLE

REPAIR

knuckles.

Install

nuts

and

lock

washers

on

arms

and

tighten

nuts

to

torque

specified

in

"Specifica-

tions"

at

end

of

this

section.

Secure

nuts

with

cotter

pins.

11.

Install

brake

spider

and

camshaft

assem-

bly

on

knuckle,

install

brake

chambers,

and

con-

nect

chamber

push

rods

to

slack

adjusters.

Install

brake

shoes,

hubs

and

bearings,

and

brake

drums.

Refer

to

HUBS,

WHEELS,

AND

TIRES

(SEC. 19)

for

instructions

for

adjusting

wheel

bearings.

12.

Install

tie

rod

assembly,

then

on

vehicles

equipped

with

mechanical

steering,

connect

drag

link

to

steering

arm;

on

vehicles

equipped

with

power

steering,

connect

extension

and

end

socket

assembly

to

steering

arm

as

directed

in

STEERING

(SEC.

16) of

this

manual.

TIE

ROD

Tie

rod

assembly

is

three-piece

unit

com-

prised

of a

rod

and

two

end

assemblies.

Rod

is

threaded

into

ends

and

locked

with

clamp

bolts.

Right-

and

left-hand

threads

are

provided

on

tie

rod

to

facilitate

toe-in

adjustment.

Tie

rod

ends

(fig.

2)

are

constructed

to

auto-

matically

compensate

for

wear

on

bearing

surfaces.

Tie

rod

end

stud

is

held

in

contact

with

bearing

surfaces

by

tension

of

spring

which

holds

seat

firmly

against

inner

end

of

stud.

Tie

rod

end

parts

are

held

in

place

by

a

retaining

plug

and

lock

ring.

Normal

wear

on

bearing

surface

in

tie

rod

end

will

cause

increase

in

overall

height

of

assembly.

If

excessive

play

is

noted,

the

parts

which

are

worn

must

be

replaced,

or

a new

tie

rod

end

as-

sembly

must

be

installed.

18

17161514

13

1 Dowel Pin

10

Clamp Bolt

2 Dust

Seal

Washer

11

Tie Rod

3 Dust Seal Spring

12

Bolt Nut

4

Steering

Arm

13

Tie Rod

End

5 Stud Nut

14

Grease

Seal

6 Stud 15 Lock Ring

7 Dust Seal

16

Retaining Plug

8

Dust Seal

Retainer

17 Seat Spring

9

Stud Bearing 18 Spring Seat

TPM7753

Figure

2-Tie

Rod

End

Sec.

1

Page 8

GM

COACH

MAINTENANCE MANUAL

FRONT

AXLE

REPAIR

TIE

ROD REMOVAL AND DISASSEMBLY

(Fig.

2)

1.

Remove

cotter

pins

and

nuts

(5)

from

tie

rod

end

studs,

support

steering

arm

to

prevent

bending,

then

drive

tie

rod

end

tapered

stud

(6)

out

of

steering

arm.

Remove

spring

(3),

dust

seal

re-

tainer

(8),

seal

(7),

and

washer

(2)

from

stud.

2.

Loosen

clamp

bolts

(10),

then

remove

tie

rod

end

assembly

from

tie

rod

(11).

3.

Pry

end

plug

lock

ring

(15) out

of

groove

in

end

(13);

then

remove

plug

(16),

seat

and

spring

(17

and

18),

and

grease

seal(14).Stud(6)

and

bear-

ing

(9)

assembly

can

now

be

removed

from

body.

INSPECTION

Clean

all

parts

of

tie

rod

and

then

inspect

parts

for

wear

and

check

tension

of

spring

(17,

fig.

2).

Discard

worn

parts

and

replace

spring

if

broken

or

weak.

TIE

ROD ASSEMBLY AND INSTALLATION

(Fig.2)

1.

Lubricate

parts

with

lubricant

specified

in

LUBRICATION (SEC. 13)

before

assembling

tie

rod

ends.

2.

Insert

end

stud

(6) and

bearing

(9)

into

tie

rod

end

(13).

Place

grease

seal

(14)

over

end

of

spring

seat

(18);

position

seat

in

tie

rod

end (13).

3.

Place

stud

seat

spring

(17)

inside

seat

(18),

lay

retaining

plug

(16) on

spring,

then

compress

spring

(17)

and

install

lock

ring

(15) in

groove

in

tie

rod

end (13).

4.

Thread

tie

rod

end

assemblies

on

tie

rod

(11),

install

clamp

bolts

(10), new

lock

washers,

and

nuts

(12). Do not

tighten

nuts

(12)

at

this

time.

5.

Carefully

clean

tapered

portion

of

tie

rod

end

studs

(6),

then

install

dust

seal

washer

(2),

dust

seal

(7),

dust

seal

retainer

(8), and

dust

seal

spring

(3) on

end

studs

in

order

named.

6.

Clean

tapered

holes

in

steering

tie

rod

arms,

position

complete

tie

rod

assembly

on

steer-

ing

arms,

then

thread

stud

nut

(5) on end

stud

(6).

Tighten

stud

nuts

to

minimum

torque

given

in

"Specifications"

at

end of

this

section,

then

tighten

nuts

until

on nut

lines

up with

cotter

holes

in

studs.

Install

new

cotter

full

size

of

hole.

FRONT

AXLE

SPECIFICATIONS

STEERING

KNUCKLE

Spindle

Diameter

At

Inner

Wheel

Bearing

At

Outer

Wheel

Bearing

Steering

Knuckle

Bushings

Inner

Diameter

..

Length

King

Bushings

Inner

Diameter

..

Outer

Diameter.

Length.

KING

Diameter

at

Top

of

..

Diameter

at

Bottom

of

..

Length

(Overall).

FITS

AND

TOLERANCES

Clearance

Between

King

Bushing

and

Knuckle

Bushing.

King

and

Lower

Knuckle

Bushing

..

2.5613"-2.5623"

..

2.1243"

-2.1248"

.

.1.7965"

-1.7975"

..

2.1775"-2.1975"

...

1.310"-1.311"

..

1.7930"

-1.7940"

.

21½2''

.

.1.3085"

-1.3095"

1.

7930"

-1.

7940"

.10¾"

..

0.0025"

-0.0045"

.

0.0025"-0.0045"

FITS

AND

TOLERANCES

(Cont.)

King

and

King

Bushing

Steering

Knuckle

Thrust.

Thrust

Adjustment.

Shim

Thickness

Available-I

eg

Spacing

Washer

Thickness

Availabte

0.001"-0.003"

0.015"

Maximum

With

Shims

and

Spacers

.0.015"

0.093", 0.125",

&

0.156"

TORQUE

SPECIFICATIONS

King

Nuts.

Steering

Arm

Nuts

Tie

Rod

End

Clamp

Bolt

Nuts

..

Tie

Rod

End

Stud

Nuts

.

350-390

ft.-lbs.

350-390

ft.-lbs.

65-80

ft.-lbs.

.150

ft.-lbs.

min.,

then

advance

to

nearest

cotter

hole

TIE

ROD

END

End

Stud

Seat

Spring

Free

Length

Resistance

When

Compressed

to

½"

Solid

Height

AXLE

CENTER

Maximum

Allowable

Twist

End

to

End

!¼"

225-275

lbs

.

13fis"

GM

COACH

MAINTENANCE MANUAL

Sec.

2

Page 9

DESCRIPTION

Rear

axle

is

a

full-floating

type,

using

a

one-

piece

axle

housing

with

housing

bowl

cover

welded

to

housing.

Housing bowl

is

located

to

the

right

of

vehicle

center

line.

Drive

pinion

assembly,

as

shown

in

figure

4,

is

mounted

at

an

angle

to

drive

gear,

thus

increas-

ing

the

tooth

contact

area

between

drive

gear

and

drive

pinion

gear

teeth.

Drive

is

transmitted

from

transmission

angle

drive

unit

through

a

propeller

shaft

to

spiral

bevel

gears,

axle

housing, and

then

to

vehicle

underframe

through

upper

and

lower

radius

rods.

Differential

and

drive

pinion

assemblies

are

both

provided

with

facilities

for

adjustment

of

bearings

and

gear

tooth

contact.

DIFFERENTIAL

CARRIER

Differential

assembly,

drive

pinion,

andpinion

cage

assembly

are

mounted

in

differential

carrier.

After

axle

shafts

have

been

removed

and

propeller

shaft

has

been

disconnected,

differential

carrier

can

be

removed

for

inspection

and

adjustment

without

removing

axle

housing

from

vehicle.

DIFFERENTIAL

ASSEMBLY

Differential

is

a

conventional

four-pinion

type,

carried

in

a

two-piece

case

mounted

on

tapered

roller

bearings.

Bevel

drive

gear

is

bolted

to

flang-

ed

half

of

differential

case.

Drive

gear

and

pinion

are

furnished

in

matched,

lapped

sets,

and

should

always

be

installed

as

such

to

assure

satisfactory

operation.

Thrust

washers

are

used

between

differential

side

gears

and

case,

also

between

differential

pin-

ions

and

case.

Differential

case

halves

are

held

together

with

special

bolts

and

slotted

nuts,

locked

in

place

with

lock

wire.

DIFFERENTIAL

SIDE BEARINGS

Differential

is

supported

in

tapered

roller

bearings

which

take

thrust

as

well

as

radial

loads.

Bearings

are

mounted

in

machined

supports

in

differential

carrier,

with

thrust

loads

taken

by

ad-

justing

rings

threaded

into

carrier

supports

and

bearing

caps.

Adjusting

rings

bear

against

bearing

cups

and

are

locked

in

position

by

adjusting

ring

locks

bolted

to

each

bearing

cap.

PINION AND CAGE ASSEMBLY

Bevel

drive

pinion

is

installed

at

an

angle

in

differential

carrier.

Pinion

is

straddle

mounted

in

two

opposed

tapered

roller

bearings

at

outer

end,

and

one

straight

roller

bearing

at

inner

end.

Tapered

roller

bearing

cups

installed

in

pin-

ion

cage

are

separated

by a

machined

shoulder

in

pinion

cage.

Spacer

of

correct

thickness

is

used

to

adjust

,Pinion

bearings

on

shaft.

Straight

roller

bearing

at

inner

end

of

drive

pinion

is

secured

in

place

with

a

retainer

ring.

Shims

of

various

thicknesses

are

used

between

pinion

cage

and

differential

carrier

to

adjust

drive

pinion

tooth

contact

and

gear

backlash.

Pinion

shaft

and

cage

assembly

cannot

be

re-

moved

from

carrier

until

differential

assembly

has

been

removed

from

carrier.

AXLE

SHAFTS AND HOUSING

Axle

shafts

are

full

floating

type.

Drive

flange

at

outer

end

is

attached

to

hub by

studs,

nuts,

and

tapered

dowels;

inner

end

of

shaft

is

splined

to

differential

side

gear.

Axle

housing

is

a one.:.piece

design

with

differ-

ential

bowl

located

off

center.

Housing

is

equipped

with

outer

end

tubes

which

are

threaded

to

accom-

modate

wheel

bearing

adjusting

nuts.

MAINTENANCE

ON

VEHICLE

The

following

maintenance

operations

should

be

accomplished

at

regular

inspection

and

lubri-

cation

intervals.

LUBRICATION

Lubrication

checking

and

draining

intervals

and

filling

instructions,

also

type

of

lubricant

and

capacity

is

given

in

LUBRICATION {SEC. 13).

Examine

pinion

oil

seal,

axle

shaft

flange

and

carrier

to

housing

gaskets

for

evidence

of

lubri-

cant

leakage.

Tighten

bolts

or

nuts,

or

replace

gaskets

and

seals

to

correct

leaks.

MOUNTING

Maintenance

of

axle

mounting on

vehicle

con-

sists

primarily

of

a

regular

and

systematic

in-

spection

of

air

suspension

units

and

radius

rods

as

directed

in

AIR SUSPENSION {SEC. 14).

AXLE SHAFT

AND

PINION CAGE MOUNTING

Axle

shafts

and

pinion

cage

are

retained

with

stud

nuts,

lock

washers,

and

split

tapered

dowels.

The

studs

must

be

straight

and

dowels

of

correct

taper

must

be

used.

There

should

always

be

a

slight

clearance

between

nuts

and mounting

flange

when

nuts

are

tight.

tll

Sec.

2

Page

10

GM

COACH

MAINTENANCE MANUAL

REAR

AXLE

1

Universal

Joint

2

Universal

Joint

Flange

Yoke

3

Drive

Pinion

Companion

Flange

4

Pusher

Screws

5

Carrier-to-Housing

Stud

6

Drain

Plug

7

Differential

Carrier

Assembly

8

Lock

Wire

9 Bolt

T-2202

Figure

1·-Rear

Axle

and

Differential Carrier

Installed

Whenever

inspection

shows

that

no

clearance

exists

between

nut

and

flange,

this

indicates

that

excessive

wear

exists

at

tapered

dowels,

studs,

or

tapered

holes

in

drive

flange.

If

stud

nuts

are

not

tightened

to

recommended

torque,

play

at

flange

and

broken

or

worn

studs

will

result

and

damaged

parts

must

be

replaced.

REAR

AXLE

REPLACEMENT

Complete

instructions

for

removal

and

install-

ation

of

rear

axle

assembly

will

be

found

in

AIR

SUSPENSIGN (SEC.

14).

DIFFERENTIAL

CARRIER

REPLACEMENT

(WITH

AXLE

IN

VEHICLE)

(Key

Numbers

in

Text

Refer

to

Figure

1)

Due

to

limited

space

between

rear

axle

and

bulkhead,

the

following

procedures

are

necessary

to

remove

and

install

the

differential

carrier

with

axle

installed

under

vehicle.

REMOVAL

1.

Place

rear

wheels

of

coach

on

10-inch

riser

blocks,

keeping

blocks

flush

with

inside

of

rear

wheels.

Block

front

wheels.

securely,

FORE

and

AFT,

to

prevent

vehicle

rolling.

2.

Remove

both

rear

axle

shafts

as

instructed

under

"Axle

Shaft

Replacement"

in

this

section.

3.

Remove

drain

plug

(6)

and

drain

lubricant

from

the

axle

housing.

4.

Disconnect

propeller

shaft

universal

joint

(1)

from

flange

yoke

at

axle,

referring

to

PRO-

PELLER

SHAFT

(SEC. 18)

in

this

manual.

Wire

shaft

to

body

understructure

to

obtain

maximum

clearance.

5.

Remove

lock

wires

(8),

bolts

(9), and

lock

washers

attaching

universal

joint

flange

yoke

(2)

to

drive

pinion

companion

flange.

Remove

flange

yoke.

6.

Remove

nut

from

bolt

attaching

each

rear

height

control

valve

link

to

bracket

at

bellows

support.

Disengage

link

bolt

from

bracket.

7.

Lift

up on

both

height

control

valve

levers

to

admit

air

pressure

into

the

rear

suspension

bellows.

Hold

levers

up

until

coach

body

has

raised

sufficiently

to

permit

installing

a

10-inch

safety

spacer

between

body

and

axle

at

each

side.

Spacers

can

be

made

from

steel

tubing

of

sufficient

diam-

eter

to

fit

over

the

axle

bumpers.

After

installing

safety

spacers,

pull

down on

both

height

control

valve

levers

to

exhaust

air

pressure

from

bellows,

permitting

coach

body

to

rest

on

safety

spacers.

8.

Remo;ve

nuts

and

lock

washers

from

studs

GM

COACH

MAINTENANCE MANUAL

Sec.

2

Page

11

3/s

X

¾

X

3¾

STEEL

STOCK

WELDED

3/a

X

¾

X

3

STEEL

STOCK

WELDED

10"

__

S'f,'_'

_,

l"

2¾"

2"

~,

~&

TAP TO

FIT

JACK

¼"

EYE

REAR

AXLE

3/16"

WIRE

CABLE

l

2"

LONG

ASSEMBLED

4"

TURN-

BUCKLE

I

i-.2¾"-

--

1--6"

7½"

l

7½"

¼"

DIA.

HOLE

DRILL

(~:

{2)

S¼"

{4

HOLES)

l

-s

..

~

- 1

r·

,

..

0

DIA.

~9½"

j

~,~~

12½"

1 i

HOLE

3"

j

1-7½"---,

1"

DIA.

HOLE

SPECIAL

PLATE

DIMENSIONS

SPECIAL

PLATE

MOUNTED ON

JACK

T-2203

Figure

2-Special

Jack

Adapter

Plates

for

Removing

Differential Carrier

(5)

attaching

differential

carrier

to

axle

housing.

Remove

all

lower

studs

from

housing,

using

a

suit-

able

stud

remover.

9.

Loosen

lock

nuts

on two

carrier-to-housing

pusher

screws

(4).

Turn

screws

in

to

startcarrier

out

of

housing.

10. A

floor

model

dolly

jack,

adapted

for

re-

moving

the

differential

assembly,

should

be

posi-

tioned

under

the

coach.

An

adapter

plate

should

be

fabricated

locally,

using

a

3/

4-inch

flat

steel

plate

and

shaped

to

fit

the

lower

portion

of

the

differen-

tial

carrier

assembly.

A

second

3/

4-inch

flat

steel

plate

must

be

fab-

ricated

to

fasten

to

the

floor

jack

and

adapter

plate

to

permit

rotation

of

the

adapter

plate.

Refer

to

figure

2.

11.

Pull

the

carrier

assembly

back

as

far

as

possible.

Tilt

the

gear

end

of

the

carrier

assembly

up

until

it

clears

the

yoke. As

the

carrier

is

moved

out

of

the

housing, move

it

down and

to

the

left

to

clear

all

obstructions.

INSTALLATION

1.

Before

reinstalling

the

carrier

assembly,

clean

mating

surfaces

of

carrier

flange

and

axle

housing.

2. Make

sure

the

carrier-to-housing

pusher

screws

(

4)

are

backed

out

so

ends

of

screws

will

not

interfere

with

carrier-to-housing

contact.

Secure

screws

with

lock

nuts.

3. Mount

the

carrier

assembly

on

the

floor

jack

using

the

same

base

plate

and

adapter

plate

used

to

remove

the

carrier.

Use

wire

or

string

to

secure

a new

gasket

to

the

carrier

flange

until

the

carrier

can

be

positioned

in

the

axle

housing.

4. With

the

carrier

securely

supported

on

the

floor

jack,

roll

under

vehicle

and

maneuver

into

position

at

axle

housing.

Start

carrier

into

housing

until

studs

extend

through

the

carrier

flange.

Re-

·

move

wire

or

string

used

to

attach

the

gasket

to

the

carrier

flange

and

transfer

gasket

to

the

studs

of

the

housing.

Use

flat

washers

and

nuts

on

four

evenly

spaced

studs

to

draw

carrier

squarely

into

the

housing.

5.

Reinstall

carrier

studs

in

lower

half

of

the

axle

housing.

Seat

studs

firmly,

using

a

suitable

stud

replacer.

6.

Remove

nuts

and

flat

washers

used

to

draw

carrier

into

position,

then.install

lock

washers

and

nuts

on

all

studs.

7.

Tighten

nuts

to

recommended

torque

value

listed

in

"Specifications"

at

end

of

this

section.

8.

Install

universal

joint

flange

yoke (2) on

drive

pinion

companion

flange

(3)

and

attach

with

bolts

(9),

lock

washers,

and

nuts.

Nuts

must

be

on

axle

side

of

companion

flange,

with

the

lock

wash-

ers

under

bolt

heads.

Tighten

firmly,

then

thread

lock

wires

(8)

through

adjacent

pairs

of

bolt

heads

and

twist

ends

of

each

wire

together.

9.

Connect

propeller

shaft

to

flange

yoke

at

axle

by

assembling

universal

joint

as

directed

in

PROPELLER

SHAFT

(SEC. 18).

10.

Install

drain

plug (7)

in

axle

housing and

tighten

firmly.

Fill

axle

housing

with

lubricant,

and

lubricate

propeller

shaft

universal

joints

as

direc-

ted

in LUBRICATION (SEC. 13).

11.

Push up on

both

height

control

valve

levers

to

admit

air

pressure

into

bellows.

Hold

levers

up

until

coach

body

has

risen

enough

to

permit

re-

moval

of

safety

spacers.

Remove

spacers.

12.

Insert

the

height

control

valve

link

bolts

through

holes

in

brackets

and

secure

with

self-

locking

nuts.

Tighten

nuts

to

recommended

torque

value

listed

in

"Specifications"

at

end of

this

section.

13.

Install

axle

shafts

as

directed

under

"Axle

Shaft

Replacement"

in

this

section.

Sec.

2

Page

12

GM

COACH

MAINTENANCE MANUAL

REAR

AXLE

1

Figure

3-Clearance

Between Nut

and

Flange

AXLE

SHAFT

REPLACEMENT

The

following

procedure

for

removal

and

in-

stallation

of

axle

shaft

is

applicable

regardless

whether

the

axle

assembly

is

removed

or

installed

on

the

vehicle.

REMOVAL

1.

Remove

nuts

and

washers

from

hub

studs.

2.

Strike

center

of

flange

with

a

lead

hammer

to

loosen

flange

and

dowels

from

studs.

3.

Withdraw

axle

shaft

from

housing,

then

re-

move

gasket

from

hub

or

flange.

NOTE:

Three

threaded

holes

are

provided

in

axle

shaft

flange

for

use

of

puller

screws,

if

nec-

essary.

INST

ALLA

TI

ON

1.

Before

installing

axle

shafts,

hubs

should

be

removed

and

bearings

cleaned,

inspected,

and

adjusted

as

directed

in

"HUBS

AND

BEARINGS"

(SEC.

19).

2.

Install

new

gasket

over

hub

studs.

NOTE:

Observe

that

oil

seal

wiper

is

in

place

on

outer

end

of

axle

housing

tube

and

oil

seal

assembly

is

in

place

on hub

studs.

3.

Dip

splined

end

of

axle

shaft

in

rear

axle

lubricant,

then

insert

shaft

into

housing,

guiding

shaft

into

side

gear

and

at

same

time

align

flange

holes

with

hub

studs.

When

studs

and

flange

holes

are

in

alignment,

push

axle

shaft

into

place.

4.

Install

split

tapereddowels,

external-tooth-

ed

lock

washers,

and

nuts

on

four

studs

at

tapered

holes

in

flange;

also

install

lock

washers

and

nuts

at

remaining

six

studs.

Tighten

nuts

alternately

and

evenly

to

recommended

torque

value

listed

in

"Specifications"

at

end

of

this

section.

5.

Observe

that

clearance

exists

between

nut

and

flange

(fig. 3). If

no

clearance

exists,

this

in-

dicates

excessive

wear

at

studs,

dowels,

or

flange

holes.

Replace

worn

parts

if

necessary.

AXLE

OVERHAUL

DISASSEMBLY

tive

sections

of

this

manual.

Rear

axle

may

be

disassembled

while

housing

remains

installed

in

vehicle

if

proper

equipment

is

available

for

handling

differential'assembly.

Infor-

mation

on

suspension,

propeller

shaft,

brakes,

hubs,

bearings,

wheels,

and

tires

will

befoundinrespec-

The

following

instructions

provide

procedures

for

complete

disassembly,

cleaning,

inspection,

repair,

and

reassembly

of

rear

axle.

Axle

housing

may

be

checked

for

bent

condition

before

axle

as-

sembly

is

removed

from

coach.

The

following

re-

pair

procedure

is

based

on

the

operations

neces-

1

Drive

Gear

18 Pinion

Cage

Tapered

Dowel 33 Pinion

Bearing

Spacer

2

Differential

Case

19

Lock

Washer

34 Pinion

Bearing

Cup -

Inner

3

Differential

Spider

20 Stud Nut 35 Pinion

Bearing

Cone

-

Inner

4 Pinion

Thrust

Washer

21

Pinion

Cage

Stud 36

Drive

Pinion

5

Case

Bolt Nut

22

Pinion Oil

Seal

Retainer

37 Pinion

Bearing

6

Adjusting

Ring

Lock

Gasket

38

Bearing

Retainer

Ring

7

Lock

Bolt 23 Pinion Oil

Seal

Retainer

39

Carrier

Stud

8

Bearing

Adjusting

Ring

24 Oil

Seal

Sleeve

40 Stud Nut

9

Axle

Shaft (Right) 25 Pinion Nut

41

Lock

Washer

10

Axle

Housing

26 Pinion Nut

Washer

42

Axle

Shaft

(Left)

11

Carrier

Gasket

27

Propeller

Shaft

Companion

43

Differential

Bearing

Cone

12

Side

Gear

Thrust

Washer

Flange

44

Differential

Bearing

Cup

13

Differential

Side

Gear

28

Dust

Slinger

45

Differential

Bearing

Cap

14 Bolt

Lock

Wire

29 Pinion Oil

Seal

Assembly

46

Differential

Bearing

Cap Stud

15

Drive

Gear

Bolt 30 Pinion

Cage

47

Differential

Bearing

Cap Nut

16

Differential

Carrier

31

Pinion

Bearing

Cone

-

Outer

48

Differential

Pinion

17 Pinion

Cage

Shims

32

Pinion

Bearing

Cup -

Outer

49

Differential

Case

Bolt

Captions

for

Figure

4-0pposite

Page

GM

COACH

MAINTENANCE MANUAL

49

2 3 4 5

37

31

30

29

28

27

26

Figure

4-Sectional

View

of

Rear

Axle

Sec. 2

Page

13

REAR

AXLE

14

15

16

17

18

19

20

21

TPM-9265-1

Sec.

2

Page 14

GM

COACH

MAINTENANCE MANUAL

REAR

AXLE

Figure

5-Bearing

Cap

Alignment

Marks

sary

when

axle

is

removed

from

coach.

Before and

during

disassembly

operations,

perform

following

inspections

and

check

all

adjust-

ments

to

determine

repairs

required.

Key

numbers

in

text

refer

to

figure

4

unless

otherwise

indicated.

AXLE HOUSING

At

regular

inspection

intervals,

or

if

condi-

tions

indicate

that

rear

axle

housing

might

be

bent,

housing

should

be

checked,

using

the

following

method.

This

check

can

be

made

before

or

after

axle

is

removed

from

coach

to

determine

if

axle

housing

is

sprung.

Conventional

camber

and

toe-

in

gauges

can

be

used

to

perform

inspection.

1.

Support

axle

in

level

position

using

blocks

at

each

support

beam;

then

check

rear

wheel

bear-

ings

for

proper

adjustment

as

instructed

in

"HUBS

Figure

6-Differential

Case

Alignment

Marks

Figure

7-Differential

Bearing

Removal

AND

BEARINGS" (SEC. 19).

2.

Check

run-out

at

each

rear

wheel

and

re-

place

wheels

having run-ciut

in

excess

of

3/32".

3.

Check

for

toe-in

andcamberatrearwheels.

Rear

wheels

should

not

toe-in

or

out

more

than

1/8",

and

camber

should be·

zero,

plus

or

minus

1/

4

degree.

If

measurements

are

not within

the

above

dimensions,

bent

or

sprung

axle

housing

is

indicated.

Make notation

of

the

existing

conditions

for

use

when making

corrections

later.

4. In

cases

where

bent

axle

housings

are

in-

dicated,

further

checks

to

determine

exact

location

of

bend

should

be

made

after

differential

carrier

has

been

removed,

then

necessary

steps

taken

to

correct

the

condition.

DIFFERENTIAL

CARRIER REMOVAL

1.

Remove

axle

shafts

as

previously

instructed

under

"Axle Shaft

Replacement"

in

this

section.

2.

Remove

drain

plug (7, fig.

1)

and

drain

lu-

bricant

from

housing.

3.

Remove

stud

nuts

(40) and

lock

washers

(41)

from

differential

carrier

studs

(39).

4.

Be

certain

that

differential

carrier

is

sup-

ported

securely,

then

proceed

to

pull

complete

carrier

assembly

out

of

housing. A

small

pinch

bar

may

be

used

to

keep

carrier

straight

in housing

bore

while

carrier

is

being

withdrawn,

provided

end

of

bar

is

rounded

to

prevent

damage

to

carrier

flange.

DIFFERENTIAL

REMOVAL

1.

Remove

lock

wire

from

adjusting

ring

lock

retaining

bolts

(7),

then

remove

locks

(6).

GM

COACH

MAINTENANCE MANUAL

Sec.

2

Page

15

2.

Remove

wires

and

nuts

(47)from

differential

side

bearing

cap

studs

(46). Make

certain

that

bearing

caps

(45)

and

carrier

are

marked

(fig.

5)

before

removal,

then

remove

side

bearing

caps

(45).

Remove

side

bearing

adjusting

rings

(8).

Lift

dif-

ferential

assembly

with

cups

(44)

from

carrier.

Remove

bearing

cups

(44)

from

bearings

(43).

DIFFERENTIAL

DISASSEMBLY

1.

Mark

both

halves

of

differential

case

(2)

so

halves

may

be

reassembled

in

original

positions

(fig.

6).

2.

Remove

lock

wire

and

nuts

(5)

from

bolts

(49)

which

hold

the

two

halves

of

differential

case

(2)

together;

then

separate

halves

of

case.

3.

Remove

side

gears

(13),

thrust

washers

(12),

spider

(3),

pinions

(48),

and

thrust

washers

(4)

from

differential

case.

4.

Using

differential

bearing

remover

plug

(J-4856)

as

shown

in

figure

7,

drive

bearing

evenly

off

each

differential

case

half,

using

a

long

punch

and

hammer

as

illustrated.

5.

Remove

lock

wire(14)fromcapscrews(l5),

then

remove

cap

screws

holding

drive

gear

(1)

to

differential

case.

Remove

gear

from

case.

PINION CAGE REMOVAL

AND DISASSEMBLY

1.

Remove

nuts

(20)

and

lock

washers

(19)

which

secure

pinion

cage

(30)

to

differential

car-

rier

(16).

Tap

pinion

cage

to

loosen

and

remove

four

tapered

dowels

(18).

2.

Install

two

puller

screws(l/2"-13xl-1/2")

and

tighten

alternately

and

evenly

to

pull

cage

(30)

out

of

carrier.

Remove

shim

pack

(17)

from

pinion

cage

studs

(21).

Tie

shims

(17)

together

so

same

shim

pack

may

be

used

at

reassembly.

3.

Remove

retainer

ring

(38)

which

secures

inner

bearing

(37) on

drive

pinion

(36);

then

re-

move

inner

bearing

from

drive

pinion

using

uni-

versal

puller

(J-8176)

and

arbor

press

in

manner

illustrated

in

figure

8.

4.

Clamp

pinion

in

vise

equipped

with

soft

jaw

plates.

Remove

cotter

pin,

nut

(25),

and

washer

(26)

from

drive

pinion

(36).

5.

Using

suitable

puller,

remove

propeller

shaft

companion

flange

(27)

from

drive

pinion

(36).

6.

Remove

cap

screws

and

lock

washers

from

pinion

oil

seal

retainer

(23),

then

remove

retainer

and

gasket.

7.

Place

cage

and

drive

pinion

assembly

in

an

arbor

press

and

press

drive

pinion

(36)

out

of

flange

(27)

and

pinion

cage.

Outer

bearing

(30)

will

remain

in

pinion

cage.

8.

Remove

bearing

adjusting

spacer

(33)

from

drive

pinion

(36)

and

tag

for

reassembly

reference.

9.

If

necessary,

inner

bearing

cone

(31)

can

be

removed

from

pinion

with

universal

puller

(J-8176)

and

arbor

press

as

illustrated

in

figure

8.

REMOVING INNER

BEARING CONE

REAR

AXLE

REMOVING INNER

ROLLER

BEARING

TPM-8480

Figure

8-Pinion

Bearing

Removal

10.

Remove

oil

seal

(29)

assembly

from

pin-

ion

cage.

11. When

inspection

indicates

necessity,

cups·

(32

and

34)

can

be

removed

from

cage,

using

re-

mover

(J-3940)

in

manner

illustrated

in

figure

9.

CLEANING, INSPECTION,

AND

REPAIR

(Key

Numbers

in

Text

Refer

to

Figure

4)

CLEANING BEARINGS

The

importance

of

proper

bearing

cleaning

cannot

be

over-emphasized.

Bearings

should

al-

Bearing

Cage

Figure

9-Pinion

Cage

Bearing

Cup

Removal

Sec.

2

Page 16

GM

COACH

MAINTENANCE MANUAL

REAR

AXLE

ways

be

cleaned

separately

from

other

rear

axle

parts.

When

cleaning

bearings,

be

sure

to

perform

all

of

the

following

steps:

1. Soak

differential

and

drive

pinion

bearings

in

clean

kerosene,

Diesel

fuel

oil,

or

other

clean-

ing

solvent.

Gasoline

should

not

be

used

as

a

bear-

ing

cleaner.

Also,

bearings

should

never

be

placed

in

a hot

solution

tank

for

cleaning.

2.

After

old

lubricant

is

loosened,

hold

bear-

ing

races

so

that

bearings

cannot

rotate,

then

brush

bearings

with

soft

bristled

brush

until

all

grit

and

dirt

has

been

removed.

3.

Rinse

bearings

in

clean

fluid;

then,

while

holding

races,

blow

dry

with

compressed

air.

Be

sure

air

stream

is

moisture

free.

4.

Inspect

bearings

as

instructed

under

'1n-

spection

Operations"

later

in

this

section.

If

bear-

ings

pass

inspection,

dip

bearings

in

differential

lubricant

recommended

in

LUBRICATION (SEC.

13);

then

wrap

bearings

in

clean

cloth

or

paper

until

ready

to

reassemble

axle.

CLEANING PARTS

Immerse

all

parts

in

suitable

cleaning

fluid

and

clean

parts

thoroughly.

Use

a

stiff

bristle

brush

to

remove

all

old

lubricant.

Remove

par-

ticles

of

gaskets

which may

adhere

to

matingfaces

of

axle

housing,

differential

carrier,

hubs,

and

axle

shaft

flanges.

Clean

out

lubricant

channels

in

pinion

cage

and

differential

carrier.

Clean

housing

breather.

Make

certain

that

interior

of

axle

housing

is

thoroughly

cleaned.

INSPECTION

Whenever

available,

the

Magna-Flux

method

should

be

used

on

all

steel

parts,

except

ball

and

roller

bearings.

This

method

is

especailly

suited

for

inspection

of

ground

or

highly

finished

sur-

faces

for

wear

and

cracks

which

otherwise

would

not

be

visible.

INSPECTION OPERATIONS

1.

Bearings.

Rotate

each

bearing

slowly,

and

at

the

same

time

examine

bearing

for

roughness,

damage,

defects,

or

wear.

Note

condition

of

bear-

ing

cage.

Replace

bearing

if

cage

is

damaged

or

if any

of

the

conditions

previously

noted

exist.

2.

Gears.

Examine

drive

gear,

drive

pinion,

and

differential

gears

for

damaged

teeth,

worn

spots

in

surface

hardening,

and

distortion.

If

either

drive

gear

(1)

or

drive

pinion

(36)

are

worn

or

damaged,

both

must

be

replaced

as

a

matched

set.

Never

replace

drive

pinion

or

drive

gear

separ-

ately.

Check

differential

pinions

(48)

for

excessive

wear,

and

fit

on

spider

(3).

Refer

to

"Specifications"

at

end

of

this

section

for

limits.

Check

radial

clear-

ance

between

differential

side

gear

hubs and

dif-

ferential

case.

3.

Differential

Case.

Inspect

differential

case

assembly

(2)

for

cracks,

distortion,

or

damage.

If

case

is

in good condition,

thoroughly

clean

case

and

cover;

then

assemble

case

with

bolts

and

mount

in

lathe

centers

or

"V"

block

stand.

If

lathe

is

not

available,

install

differential

side

bearings

and

mount

case

in

differential

carrier

as

directed

under

"Differential

Assembly

Installation"

later

in

this

section.

Install

dial

indicator

and

check

dif-

ferential

case

run-out.

Refer

to

"Specifications"

at

end

of

this

section

for

run-out

limits.

When-

ever

run-out

exceeds

limits,

differential

case

run-

out

may

be

corrected

as

later

described

under

"Re:-

pair"

in

this

section.

4.

Axle

Shafts.

Examine

splined

end

of

axle

shaft

(9 and 42)

for

twisted

or

cracked

splines,

twisted

shaft,

or

damaged

flange.

If

any

of

above

conditions

are

evident,

install

new

axle

shafts.

5. Axle Shaft and

Flange

Run-Out.

Install

axle

shaft

assembly

in

lathe

centers

or

"V"

blocks.

Check

shaft

run-out

with

dial

indicator;

if

run-out

exceeds

limits

listed

in

"Specifications"

at

end

of

this

section,

discard

axle

shaft.

Position

dial

in-

dicator

so

that

indicator

shaft

end

contacts

inner

surface

of

flange

near

outer

edge,

then

check

flange

run-out.

If

run-out

exceeds

iimits

listed

in

"Speci-

fications"

at

end

of

this

section,

discard

axle

shaft.

6. Axle Housing.

If

check

made

prior

to

dis-

assembly

of

axle

indicated

a

bent

condition

at

axle

housing

(10),

make

more

complete

check

of

hous-

ing

on

surface

plate

to

determine

extent

of

damage.

If

inspection

indicates

a

sprung

or

bent

condition,

axle

housing

should

be

discarded.

Straightening

of

axle

forgings

is

not a

recommended

operation.

7.

Oil

Seal.

Replacement

of

oil

seal

(29) when

unit

is

disassembled

is

more

economical

thanpre-

mature

overhaul

to

replace

this

part

at

a

future

time.

Further

loss

of

lubricant

through

a

worn

seal

may

result

in

failure

of

other

parts,

such

as

gears

and

bearings.

Handle

seal

carefully,

particularly

when

being

installed.

Cutting,

scratching

or

curling

under

of

lip

of

seal

seriously

impairs

efficiency

of

seal.

Use

of

Permatex

or

equivalent

around

outer

diam-

eter

of

seal

is

recommended

to

insure

against

leakage

at

this

point.

8. Oil

Seal

Sleeve.

Carefully

inspect

oil

seal

sleeve

(24)

at

propeller

shaft

companion

flange

for

any

pitted,

corroded,

or

worn

condition

at

oil

seal

contact

surface.

If

such

imperfections

cannot

be

cleaned

up by

polishing,

the

sleeve

must

be

replaced.

REPAIR

1.

Differential

Case.

Excessive

run-out

on

differential

case

may be

corrected

by

machining

flange

on

gear

side

of

case.

Remove

sufficient

metal

GM PD-4107 User manual

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