Meritor RS 120 User manual

SINGLE REDUCTION AXLE
RS 120 - Rear Axle
FIELD MAINTENANCE MANUAL
_________________________________________________
Meritor H S (India) Limited,
Plot No: 36, Hootagalli Industrial Area,
Off Hunsur Road, Mysore-570 0 8
Ph: [phone] Fax: [phone]
Phone: [phone] fascimile:[phone]

2
Table of Content
1. INTRODUCTION.................................................................................................................................03
2. DISASSEMBLY
Removal Differential Carrier from Axle Housing .....................................................................04
Removal Main Differential Case and Ring Gear Assembly...................................................05
Disassemble Main Differential Case and Ring Gear Assembly ..........................................0
Removal and Disassemble Drive Pinion Assembly .................................................................10
3. GENERAL INFORMATION
Dri-Loc Fasteners, Meritor Liquid Adhesive and Loctite 277 ............................................13
Application of Silicone Gasket Material ........................................................................................14
4. RE ARE ARTS FOR ASSEMBLY
Clean Ground and Polished Parts.....................................................................................................18
Inspect Parts...............................................................................................................................................19
Repair or Replace Parts ........................................................................................................................21
Repair Axle by Welding.........................................................................................................................21
5. ASSEMBLY
Assembly of Carrier…………………………………………………………………………………………..24
Adjust Thickness of Shim Pack for Hypoid Pinion...................................................................29
Assemble Main Differential and Ring Gear..................................................................................30
Check Rotating Resistance of Differential Gears ......................................................................31
Install Differential and Ring Gear Assembly...............................................................................32
Adjust Preload of Differential Bearings ........................................................................................33
Check Run out of Ring Gear ................................................................................................................34
Adjust Backlash of Ring Gear .............................................................................................................35
Check Tooth Contact Pattern of Ring Gear Set ..........................................................................3
Adjust Preload of Pinion Bearings...................................................................................................38
Install Differential Carrier into Housing.......................................................................................40
6. LUBRICATION.....................................................................................................................................41
7. FASTENER TORQUE CHART.......................................................................................................43
8. ADJUSTMENT AND S ECIFICATION......................................................................................45

3
Introduction
Standard Single-Reduction Carriers
Meritor single-reduction standard carriers, Figure Below, are used in most Meritor
single axles, rear of tandem axles and front drive steering axles. The single-reduction
carrier models are front mounted into the axle housing. These carriers have a hypoid
drive pinion and ring gear set and bevel gears in the differential assembly.
A straight roller bearing (spigot) is mounted on the head of the drive pinion. All other
bearings in the carrier are tapered roller bearings.
When the carrier operates, there is normal differential action bet een the heels all the
time.

4
Disassembly
I. REMOVAL OF DIFFERENTIAL CARRIER FROM AXLE HOUSING:
Figu e 1
1. Raise the rear end of the vehicle
put on jack stands Figure1.
2. Disconnect the propeller
shaft from input flange. Figure 2.
remote drain plug and drain
differential oil.
•Disconnect the vehicle
air line from the differential
lock actuator assy.
Jack Stands
Figu e 2

5
Disassembly
Driving
lugs
Repair
Stand
Differential
Carrier
. Use tool (A) to stop rotation of
wheel end assembly and undo screws
(B) fastening axle drive shaft to wheel
hub. Figure .
•Remove axle shafts using
extraction holes.
• Remove all the carrier mounting
fasteners.
•Remove the carrier from the
housing.
•Mount the carrier on a repair
stand Figure 4.
Figu e 4
Figu e 3

6
Disassembly
II DISASSEMBLY OF DIFFERENTIAL
Bearing Cap
Carrier Leg
Match Marks
Figu e 5
Figu e 6
• If the same gear set is to be
reused record the backlash
before disassembly. Figure 5.
1. Make match marks on one
Carrier leg and bearing cap.
Figure 6

7
Disassembly
Removing
Cotter Key
. Remove cotter pin using a small
drift and hammer. Figure 7.
•Remove cap screw, washers and
lock plate. Figure 8.
Figu e 7
Figu e 8

8
Disassembly
Bearing
Cap
4. Remove cap screws and washers of
bearing caps. Figure 9.
• Remove bearing adjusting
rings
5. Lift the differential case
& ring gear assembly Figure 10.
Figu e 9
Figu e 10

9
Disassembly
Match Marks
Match Marks
Trust
Washer
Side
Gear
6. Make match makes on the
diff. case halves. Figure 11.
7. Remove the diff. case bolts.
separate case halves. Remove
spider, pinions, side gears and
thrust washers. Figure 12.
Figu e 11
Figu e 12

10
Disassembly
Case Half
Press
Plate
Press
Puller
Flange
Bar
8. Remove the ring gear
bolts and nuts.
• Remove the ring gear from
diff.case using a press
Figure 1 .
9. Remove the bearings from
diff. cases using bearing
puller/press Figure 14.
.
10. Fasten a flange bar to the
companion flange
• Remove pinion nut and
washer Figure 15.
Figu e 13
F
igu e 14
Figu e 15

11
Disassembly
DRIVEPINIONAND
BEARINGCAGE
SHIMS
Press
Drive Pinion
Oil Seal
Bearing.
Cage
Support
Support
11. Remove the companion flange
using a suitable puller, Figure 16.
• Remove cap screws and
washers of bearing Cage,
• Remove bearing Cage and
shims
• Measure and note down
the total thickness of
removed shims.
12. Remove drive pinion from
bearing Cage
using a press. Figure 17.
Figu e 16
Figu e 17

12
Disassembly
Pinion
Bearing cage
Inner Bearing
Cone
Dr
ive Pinion
Bearing
Support
Bearing Puller
1 . Remove the oil seal. figure18
• Take out the outer bearing
cone.
• Remove the bearing cups from
the cage using a small drift and
hammer.
14. Remove the inner bearing cone
using the split puller and
press.Figure 19.
15. Remove the snap ring .
• Remove the spigot bearing
using the puller Figure 20.
Figu e 18
Figu e 19
Figu e 20

13
General Information
Use of Dri-Loc Fasteners and
Meritor Liquid Adhesive 2297-
C- 747 or Loctite 277
Install New Dri-Loc Fasteners :
1. Clean the oil and dirt from threaded
holes. There is no special cleaning
required.
2. Assemble parts using the new Dri-
Loc fasteners.
!
CAUTION:
Do not apply adhesives or sealants on
new Dri-Loc fasteners or in the
threaded holes. If other adhesives or
sealants are used, the new Dri-Loc
adhesive will not function correctly.
Tighten the Dri-Loc fasteners to the
required torque alue for that size
fastener. There is no special procedure
or torque alue required. See the torque
chart
T
NOTE:
There is no drying time required for
Dri-Loc fasteners.
Install Old Dri-Loc Fasteners Using
Meritor Liquid Adhesive 2297-C-
747 or Loctite 277:
1. Clean the oil and dirt from threaded
holes. There is no special cleaning
required and it is not necessary to
remo e the old Dri-Loc adhesi e
from the threads.
2. Apply four or fi e drops of Meritor
Liquid Adhesi e or Loctite 277 to the
threaded holes ONLY. Make sure the
adhesi e is on the threads. Figure21.
!
CAUTION:
Do not apply adhesive to the fastener
threads. Air pressure in the hole will
push the adhesive out as the fastener
is installed.
3. Tighten the fasteners to the required
torque alue for that size fastener.
There is no special procedure or
torque alue required. See the
torque chart
T
Figure 21

14
General Information
NOTE:
There is no drying time required for
Meritor Liquid Adhesive 2297-C-
747 or Loctite 277.
Check Torque Values of Dri-Loc
Fasteners Not Requiring
Removal:
!
CAUTION:
If Dri-Loc fasteners do not require
removal from the component, check
the component for correct torque
value as follows:
1. Apply the MINIMUM amount of
torque required for that size
fastener. See the torque chart The
fastener MUST NOT rotate.
T
2. If the fastener rotates any amount,
remo e the fastener from the
component and apply adhesi e to
the threaded hole. Follow the
procedure for installing old Dri-Loc
fasteners.
Remove Dri-Loc Fasteners:
If it is difficult to remo e Dri-Loc
fasteners from components, the
strength of Dri-Loc, Meritor adhesi e or
Loctite 277 can be decreased by heating.
Use the following procedure:
1. Heat the fastener for three to fi e
seconds ONLY and try to loosen the
fastener with a wrench. DO NOT
use an impact wrench to loosen the
fastener or hit the fastener with a
hammer.
2. Repeat Step 1 until the fastener can
be remo ed.
!
CAUTION:
Do not exceed 50° F. (+177
0
C.)
maximum. Heating must be done
slowly to prevent thermal stresses in
the other components.
Application of Silicone Gasket
Material
NOTE:
The following silicone gasket
products can be used on Meritor
components.
1. General Electric No. RTV-1473 black.
2. From Meritor Automoti e, Inc.:
•0.4 kg tube Part No. 1199-Q-2981
!
WARNING:
Small amounts of acid vapor are
present when silicone gasket
material is applied. To prevent
possible Injury, be sure there is good
ventilation In the work area. If
silicone gasket material gets in your
eyes, flush your eyes for 15 minutes
with water. Have your eyes checked
by a doctor.

15
General Information
1. Remo e all old gasket material
from both surfaces.
2. Clean the surfaces where silicone
gasket material will be applied.
Remo e all oil, grease, dirt and
moisture.
3. Dry both surfaces.
4. Apply a 0.125 inch diameter
continuous bead of the silicone
gasket material around one
surface. Also apply the gasket
material around the edge of all
fastener holes in that surface.
Figure 22.
!
CAUTION:
The amount of silicone gasket
material applied must not exceed
a.125 Inch diameter bead. Too much
gasket material can block lubrication
passages.
5. Assemble the components
immediately to permit the silicone
gasket material to compress e enly
between the parts. Tighten fasteners
to the required torque alue for that
size fastener. There is no special
procedure or torque alue required
See Torque Chart .
6. Wait 20 minutes before the
assembly is filled with lubricant.
Gear Set Information (Drive
Pinion and Ring Gear Marks)
0.125” (3.2 mm)
DIA. Silicon bead
gasket
NI=OI=PI=Q=léíáçå=
1.
PART NUMBER
2. TOOTH COMBINATION
NUMBER
3.
GEARSET
MATCHING
NUMBER
4. PINION CONE
VARIATION
NUMBER
1,2
1, 2, 3, 4 Option
PI=Q
=
3, 4
1, 2, 3
Figure 22
Fig
ure 2

16
General Information
NOTE:
Before a new gear set is installed in
the carrier, read the following
Information. ALWAYS CHECK THE
GEAR SET FOR CORRECT MARKS TO
MAKE SURE THE GEARS ARE A
MATCHED SET.
The location of the marks are shown in
Figure 23.
1. Part Number:
A. Examples of gear set part
numbers: Ring gear – A–2–
C0138 pinion – A–C0138.
B. Location on Dri e Pinion: End
at splines.
C. Location on Ring Gear: Front
face or outer diameter.
2. Tooth Combination Number:
A. Example of a tooth
combination number: 5-37.
NOTE:
A 5- 7 gear set has a 5 tooth drive
pinion and a 7 tooth ring gear.
B. Location on Dri e Pinion: End
at splines.
C. Location on Ring Gear: Front
face or outer diameter.
3. Gear Set Match Number:
Meritor dri e pinions and ring gears are
a ailable only as matched sets. Both
gears of a set ha e the same match
number.
A. Example of a gear set match
number: 07 B 1234.
NOTE:
A gear set match number has any
combination of a letter and number.
B. Location on Dri e Pinion: End
of gear head.
C. Location on Ring Gear: Front
face or outer diameter.

17
General Information
4. Pinion Cone Variation Number:
NOTE:
The pinion cone variation number is not used when checking for a matched gear
set. The number is used when you adjust the depth of the pinion In the carrier.
See the procedure for adjusting the shim pack thickness under the pinion cage.
A. Examples of pinion cone ariation numbers: PC+3, PC-5, +2, -1, +.01 mm or -
0.02mm
B. Location on Gear Set: End of pinion gear head or outer diameter of ring gear.
Figure 24.
PINION
CONE
VARIATION
NUMBER
Figure 24

18
Prepare Parts for Assembly
Clean Ground and Polished
Parts
1. Use a cleaning solvent to clean
ground or polished parts or surfaces.
Kerosene or diesel fuel oil can be
used for this purpose. DO NOT USE
GASO INE.
!
WARNING:
Be careful when using cleaning
sol ents. Follow the sol ent
manufacturer's Instructions for safe
use to pre ent Injury.
2. Use a knife if required, to remove
gasket material from parts. Be
careful not to damage the ground
surfaces.
3. To prevent corrosion, DO NOT clean
ground or polished parts in a hot
solution tank, water, steam or
alkaline solutions.
Clean Rough Parts
1. Clean rough parts the same as
cleaning ground and polished parts.
2. Rough parts can be cleaned in hot
solution tanks with a weak alkaline
solution.
3. Parts must remain in hot solution
tanks until completely cleaned and
heated.
!
WARNING:
Be careful when using hot solution
tanks and alkaline solutions. Follow
the alkaline manufacturer's
Instructions for safe use to pre ent
injury.
4. Parts must be washed with water
until the alkaline solution is
removed.
Dry Parts That Ha e Been
Cleaned
1. Parts must be dried immediately
after cleaning and washing.
2. Dry the parts using soft clean paper
or cloth rags.
3. Except for bearings, parts can be
dried with compressed air.
!
CAUTION:
Damage to bearings can be caused if
dried by rotating with compressed
air.
Pre ent Corrosion and Rust on
Cleaned Parts
1. Apply axle lubricant to cleaned and
dried parts that are not damaged
and are to be immediately
assembled.
2. If parts are to be stored, apply a
special material and paper that
prevents corrosion and rust to all
surfaces.

19
Prepare Parts for Assembly
Inspect Parts
It is very important to inspect all parts
carefully and completely before the axle
or carrier is assembled. Check all parts
for wear or stress and replace damaged
parts. Replacement of damaged parts
now, will prevent complete failure of the
assembly later.
1. Inspect tapered roller bearings:
Inspect the cup, cone, rollers and
cage of all tapered roller bearings in
the assembly. If any of the following
conditions exist, the bearing MUST
be replaced.
A. The center of large diameter end of
rollers worn level with or below the
outer surface. Figure 26.
B. The radius at large diameter end of
rollers worn to sharp edge.Figure26.
C. A visible roller groove in the cup or
cone inner race surfaces. The groove
can be seen at the small or large
diameter end of both parts.
Figure25.
D. Deep cracks or breaks in the cup,
cone inner race or roller surfaces.
Figure 25.
E. Bright wear marks on the outer
surface of the roller cage. Figure 27.
WORN RADIUS
WORN SURFACE
CRACK
WEAR
GROOVE
WEAR MARKS
Figure 25
Figure 26
Figure 27

20
Prepare Parts for Assembly
F. Damage on rollers and on surfaces of
the cup and cone inner race that
touch the rollers. Figure 28.
G. Damage on the cup and cone inner
race surfaces that touch the rollers.
Figure 29.
2. Inspect hypoid pinions and gears (or
wear or stress). Gears that are
damaged MUST be replaced.
!
CAUTION:
Hypoid dri e pinions and ring gears
are machined in a matched set. When
a dri e pinion or ring gear of a
hypoid gear set needs to be replaced,
both gears must be replaced at the
same time.
3. Inspect the main differential
assembly: Inspect the following
parts for wear or stress. Parts that
are damaged MUST be replaced.
A. Inside surfaces of both case halves.
B. Both surfaces of all thrust washers.
C. The lour trunnion ends of the spider
(cross).
D. Teeth and splines of both differential
side gears.
E. Teeth and bore of all differential
pinions.
!
CAUTION:
Always replace thrust washers,
differential side gears and pinions in
sets. A higher stress on parts and an
early failure of the assembly will
occur if a new part is used with parts
that are old.
4. Inspect axle shafts:
A. Inspect axle shafts for wear, stress
and cracks at the flange, shaft and
splines. Replace axle shaft if
required.
ETCHING & PITTING
SPA ING & F AKING
Figure 28
Figure 29