Eaton 1 Series Owner's manual

January, 1990
Eaton®
Hydrostatic Variable Motors
Series 1 Models 33-64
Hydrostatic Variable Motors
Repair Information

2
Table of Contents page
ID Tag ........................................................................................................................................................... 3
Required Tools.............................................................................................................................................. 3
Introduction and Part Names ........................................................................................................................ 4
Exploded View Drawing ................................................................................................................................ 5
Minor Repairs: ............................................................................................................................................. 6
Control Valve Inspection......................................................................................................................... 6
Orifice Installation ................................................................................................................................... 7
Shaft Seal Replacement.........................................................................................................................8
Valve Block Inspection ........................................................................................................................... 9
Major Repairs: Disassembly ................................................................................................................... 11
Shaft Seal and Control Valve ............................................................................................................... 11
Valve Block........................................................................................................................................... 12
End Cover and Servo Pistons .............................................................................................................. 14
Mounting Flange, Servo Pistons and Trunnions................................................................................... 16
Swashplate, Shaft and Cylinder Block.................................................................................................. 18
Major Repairs: Reassembly .................................................................................................................... 19
Slipper Clearance ................................................................................................................................. 19
Trunnions and Servo Pistons ............................................................................................................... 20
Minimum Displacement Setting ............................................................................................................21
Mounting Flange, End Cover Bearing and Shaft End Play................................................................... 24
End Cover, Valve Block and Control Valve .......................................................................................... 26
Shaft Seal ............................................................................................................................................. 28
Special Tools............................................................................................................................................... 28
Hydraulic Fluid Recommendations ............................................................................................................. 30

3
Eaton Corporation
Hydraulics Division
Spencer, Iowa 51301
Rotation
Serial No.
Model No.
Eaton
0000 00 - 000
00 00 000000
• 9/64 in. Hex Key • Small Screwdriver (1/8 in. Blade)
• 1/4 in. Hex Key • Hammer ( steel and Plastic)
• 1/2 in. Socket • Depth Micrometer
• 9/16 in. Socket • Slide Hammer
• 5/8 in. Socket • Split Blade Bearing Puller
• 3/4 in. Socket • Prick Punch
• 7/8 in. Socket • Scribe
• 1 in. Socket • Punch
• 1-3/8 in. Socket • Arbor Press
• Dial Indicator with Magnetic Base • Clean, Lint Free Cloths
• Spring Compression Scale (0-10 lbs) • Loctite
• No. 5 or 7 Retaining Ring Pliers • Light Petroleum Jelly
• Adjustable joint Pliers • Suitable Solvents and Cleaners
• 3 in.X 1/4-20 Bolt • Rotating Seal Puller (Special)
• Breaker Bar or Ratchet Wrench • Low Clearance Bearing Puller (Special)
• Torque Wrench (200 lb-ft capacity) • Bearing Cone Driver (Special)
• 18 to 20 in. Adjustable Wrench
Required Tools
Special Tools are shown on pages 28 and 29.
ID Tag
A- Displacement (cu.in./rev.)
0033 = 3.3
0039 = 3.9
0046 = 4.6
0054 = 5.4
0064 = 6.4
0076 = 7.6
B- Identifies Type of Product
21 = Variable Displacement Pump
31 = Fixed Displacement Motor
41 = Variable Displacement Motor
C- Identifies Specific Unit Configuration
D- Month of Manufactur
E- Year of Manufacture
F- Specific Serial Number of Unit
G- Identifies Direction of Input Shaft (Pumps Only) Rotation
Observed from Shaft End of Unit
CW = Clockwise
CCW = Counterclockwise
EF
ACB
G
D

4
Introduction and Part Names
Introduction
This manual provides service information for Eaton Models 33 thru 64 Variable Motors. It’s divided into two main
sections: the first covers minor repairs and the second gives instructions for the complete disassembly, inspection
and reassembly of the motor.
The following recommendations apply to both minor and major repairs:
• Most repairs require the removal of the motor from the vehicle.
• Cleanliness is extremely important.
• Clean the port areas thoroughly before disconnecting the hydraulic lines.
• Plug the motor ports and cover the open end of the hydraulic line immediately after they’re disconnected.
• Drain the oil and clean the exterior of the motor before making repairs.
• Wash all metal parts in clean solvent.
• Use compressed air to dry the parts. Do not wipe them dry with paper towels or cloth; Lint in a hydraulic system
will cause damage.
• The compressed air should be filtered and moisture free.
• Always use new seals when reassembling hydraulic motors.
• For replacement parts and ordering information refer to parts list 6-132.
• Lubricate the new seals with a petroleum jelly like Vaseline before installation.
• Torque all bolts over gasketed joints, then repeat the torquing sequence to make-up for gasket compression.
• Verifying the accuracy of motor repairs on an authorized test stand is essential.
♦ Parts used as required.
Models 33 thru 64 Variable Motor Parts
Item
No. Description Qty. Item No. Description Qty.
1 Shaft Seal Kit 1 32 Trunnion Shims ♦
2 O-ring 1 34 Plug and O-ring 1
3 O-ring 1 35 Motor Housing 1
4 Mounting Flange Bolt 12 36 Servo Piston S/A 2
5 Shipping Strap 2 37 Retaining Ring 4
6 Mounting Flange S/A 1 38 Pin 2
7 Bearing Cup 1 39 O-ring 2
8 Dowel Pin 7 40 O-ring 2
9 Mounting Flange Gasket 1 41 Servo Sleeve 2
10 Drive Shaft S/A 1 42 Servo Sleeve Retainer 2
11 Replacement Bearing Kit ♦43 Cap Screw 6
12 Swashplate S/A 1 44 End Cover Gasket 1
13 Thrust Plate 1 45 Replacement Bearing Kit ♦
14 Rotating Group 1 46 Shaft Shims ♦
15 Piston and Slipper S/A 9 47 End Cover 1
16 Slipper Retainer Plate 1 52 End Cover Bolt 6
19 Retaining Strap and Bolts 2 53 End Cover Bolt 2
20 Cylinder Barrel 1 54 Valve Block Option 1
21 Bearing Plate 1 63 Hose Fitting ♦
22 Valve Plate 1 65 Hose ♦
23 Control Valve Option 1 71 Servo Piston with Spacer 1
28 Trunnion Bolt 6 72 Spacer Shims ♦
29 Trunnion S/A 2 73 Servo Piston Spacer 1
30 Replacement Bearing Kit ♦74 Spacer Bolt 1
31 O-ring 2

5
Exploded View Drawing
© Copyright 1990 Eaton Corporation
Seals
Valve Block
53
63
47
45 46
43
42
35
34
36
39 40
41
65
854
51
52
44
73
74
36
71
72
20
21
22
8
16
19
13 15
37
38
12
4 5
6
7
8 9
11
10
14
23
8
Mounting Bolts
Gasket(s)
Control Valve/
Port Plate for
Slave Control
1
2 3
28 29
31
32
33
30
Mounting Bolts
Valve Block
Seals

6
This section describes the removal, inspection, and
installation of the control valve.
1Clean the control valve and the area around where it
attaches to the motor.
Important: Cleanliness is extremely important; be sure
that no contaminates get into the motor.
2 Remove the six hex head bolts that hold the control
valve to the motor.
3Lift the control valve away from the motor and
disengage the feedback linkage, see figure 2.
4Remove the control valve gasket.
5Inspect the control valve: Start by thoroughly flushing
the control valve with clean solvent. Then blow it dry
with compressed air. Be sure to blow through all of the
control valve’s internal passages.
Inspect the control valve linkage. Move the control lever
back and forth; it should move freely without binding.
There should be no free play in the feedback link or
control lever.
Check the control valve orifice; if it is plugged after
flushing replace it.
Figure 2
Feedback Linkage
Control Valve
Gasket
Minor Repair: Control Valve Inspection

7
Note: There are two types of control valve orifices:
Shallow Orifice Pocket
.058 in.
Stake in 3 Places
Control Valve
Deep Orifice Pocket
.180 in.
Control Valve
6Place a new control valve gasket on the motor.
7Connect the feedback linkage and position the control
valve on the motor.
Important: When the control valve is positioned on the
motor make sure the feedback linkage points towards
the motor’s end cover.
8Install the six hex head bolts and tighten them finger
tight.
9Move the control lever back and forth; it should move
freely in both directions and self-center. If it doesn’t
recheck the feedback linkage.
10 Tighten the six hex head bolts to 16 lb-ft [22 Nm].
The plate orifice is used in control valves that have a
shallow orifice pockets.
The orifice size is stamped on the orifice in thousandths
of an inch, example: 57 = .057 in.
Install the plate orifice so the orifice size is visible. Stake
it in three places with a center punch. Insure that the
orifice is properly seated after staking.
The plug is used in control valves that have a deep
orifice pockets.
Before installing the plug orifice be sure that the o-ring is
in place. Apply petroleum jelly to the edge of the plug
orifice and o-ring.
Carefully insert the plug orifice into the orifice pocket;
The large opening in the plug must go into the control
valve.
This section describes the removal, inspection, and installation of the control valve.
1Clean the control valve and the area around where it attaches to the motor.
Important: Cleanliness is extremely important; be sure that no contamination gets into the motor.
2 Remove the six hex head bolts that hold the control valve to the motor.
3Lift the control valve away from the motor and disengage the feedback linkage, see figure 2.
4Remove the control valve gasket.
5Inspect the control valve: Start by thoroughly flushing the control valve with clean solvent. Then blow it dry with
compressed air. Be sure to blow through all of the control valve’s internal passages.
Inspect the control valve linkage. Move the control lever back and forth; it should move freely without binding. There
should be no free play in the feedback link or control lever.
Check the control valve orifice; if it is plugged after flushing replace it.
6Place a new control valve gasket on the motor.
Minor Repair: Control Valve Inspection

8
This section describes the removal and installation of the
motor’s shaft seal.
1 Drain the oil from the motor.
2Position the motor so the shaft seal is accessible.
3Clean the area around the motor shaft and seal.
Important: Cleanliness is extremely important; be sure
that no contaminates get into the motor.
4Using a retaining ring pliers remove the retaining ring.
5Screw a 3 in. X 1/4-20 bolt into the threaded hole in
the stationary seal. Pull on the bolt to remove the seal.
6Use the special pulling tool, Owatonna Tool Co. P/N
CAS 1844, to remove the rotating seal, see figure 1. If
the special tool is not available pull out the rotating seal
with a wire bent to the shape of the puller.
Note: Detailed drawings of all special tools are given in
the back of this manual.
7Remove the o-ring; it will either be in the rotating seal
or on the shaft.
Note: Eaton recommends replacing the entire shaft
seal. Use Shaft Seal Kit P/N 990231.
Important: The metal-to-metal sealing surfaces are
critical. Clean the areas of contact with a suitable
solvent then blow them dry. The solvent must evaporate
without leaving a residue. Do not touch the sealing
surfaces after cleaning.
8 Apply petroleum jelly to the o-ring and install it in the
rotating seal
9Apply a light coating of clean hydraulic oil to the
cleaned metal sealing surface of the rotating seal.
10 Install the rotating seal using the special pulling tool
(CAS 1844).
11 Screw a 3 in. X 1/4-20 bolt into the threaded hole in
the new stationary seal. The bolt provides a convenient
means for holding the seal.
12 Apply petroleum jelly to the o-ring that is around the
largest part of the stationary seal.
13 Apply a light coating of clean hydraulic oil to the
cleaned metal sealing surface of the stationary seal.
14 Install the stationary seal.
15 Using the retaining ring pliers install the retaining ring
with the beveled side out.
Figure 1
Bolt
Rotating Seal
O-ring
Stationary Seal
Pulling Tool
Minor Repair: Seal Shaft Inspection

9
This section describes the removal, inspection, and
installation of the valve block.
1Clean the valve block and the area around where it
attaches to the motor.
Important: Cleanliness is extremely important; be sure
that no contaminates get into the motor.
2Position the motor so the valve block is accessible.
7Remove the two o-rings and back-up rings, and the
square cut seal from between the valve block and motor,
see figure 3.
8Remove the low pressure relief valve (also called the
charge pressure relief valve).
Note: The low pressure relief valve can be identified by
the notches machined into its large hex head, see figure
4.
9Mark the high pressure relief valves so they can be
reinstalled in the same ports.
Note: The three digit number stamped on each relief
valve indicates its pressure setting. Multiply this number
by ten to get the actual pressure setting (in PSI).
Examples:
11 Remove the o-rings and back-up rings from the relief
valves. The small o-ring on each high pressure relief
has a back-up ring on each side. The small o-ring on
the low pressure relief valve doesn’t have back-up rings.
12 Inspect the relief valves for damage and replace as
necessary.
Figure 4
Back-up
Rings
Notches
Low Pressure
Relief
High Pressure
Relief
O-ring
10 Remove the high pressure relief valves.
Number
Stamped on
Relief Valve Multiplier Relief Valve
Pressure
Setting
500 x10 5000 PSI
016 x10 160 PSI
Figure 3
Sq. Cut Seal
Control
Pressure
Hose
Bolt (4)
Hose Fitting
Valve Block
Back-up Ring
O-ring
3If the motor gets control pressure from the valve block
disconnect the hose at the valve block and remove the
hose fitting.
4Loosen the plugs and relief valves that are screwed
into the valve block.
5Remove the four hex head bolts that hold the valve
block to the motor.
6Remove the valve block.
O-ring
Minor Repair: Valve Block Inspection

10
Low Pressure
Relief Valve
High Pressure
Relief Valve
Gauge Port
Plugs
Valve
Block
13 Remove the gauge port plugs and o-rings.
Figure 5
Figure 6
Spool
Shuttle Valve
Plug
Valve Block
Shuttle Valve
Spring
Shuttle Valves
14 Remove the shuttle valve plugs and o-rings.
15 Remove the shuttle valve springs, spool, and valves.
16 Wash the relief valves, plugs, and shuttle valve in
clean solvent. Flush out the valve block. Blow dry the
parts with compressed air. Be sure to blow through the
internal passages of the valve block. Inspect the parts
for damage and replace as necessary.
17 Install the relief valves, shuttle valve, and plugs. Use
new o-rings and back-up rings.
Install back-up rings around the small o-rings on the high
pressure relief valves, see figure 4.
Lubricate the new o-rings with petroleum jelly before
installation.
Tighten all plugs and relief valves finger tight. They will
be torqued after the valve block is mounted on the
motor.
Back-up Ring
O-ring
Sq. Cut Seal
Hose Fitting
Figure 7
Bolt (4)
Valve Block
18 Install new o-rings and back-up rings in the grooves
around the high pressure ports as shown in figure 7.
Install a square-cut seal in the groove around the low
pressure port. Use petroleum jelly to hold these sealing
rings in place while the valve block is installed.
19 Position the valve block on the motor. Install the four
hex head bolts and tighten them to 28 lb-ft [38 Nm].
20 Tighten the high pressure relief valves to 25 lb-ft [34
Nm].
Tighten the low pressure relief valve, and shuttle valve
plugs to 80 lb-ft [108 Nm].
Tighten the gauge port plugs and control pressure fitting,
if used, to 17 lb-ft [23 Nm].
21 Connect the control pressure hose to the valve block
fitting, if used.
Note: The control pressure hose is now obsolete. Poor
motor control characteristics may be experienced when
the motor gets control pressure from the valve block. It
is best to run a separate control pressure line from the
charge pump to the motor. If possible re-plumb the
application so the control pressure hose is no longer
used. Be sure to plug the port in the valve block.
Minor Repair: Valve Block Inspection

11
Disassembly
This section describes the complete disassembly,
inspection,and reassembly of the motor. Due to the
complexity of the heavy duty motor certain
subassemblies are disassembled, inspected, and
reassembled upon removal from the motor. This
procedure insures repair accuracy and helps avoid the
loss of small parts.
When major repairs are planned it is recommended that
the process laid out in this section be followed from start
to finish.
1Clean the exterior of the motor and drain the oil.
2Position the motor so the shaft seal is accessible.
Important: Cleanliness is extremely important; be sure
that no contaminates get into the motor.
Figure 8
Pulling Tool
O-ring
Rotating Seal
Stationary Seal
Bolt
3Using a retaining ring pliers remove the retaining ring.
4Screw a 3 in. X 1/4-20 bolt into the threaded hole in
the stationary seal. Pull on the bolt to remove the seal.
5Use the special pulling tool, Owatonna Tool Co. P/N
CAS 1844, to remove the rotating seal, see figure 8. If
the special tool is not available pull out the rotating seal
with a wire bent to the shape of the puller.
Note: Detailed drawings of all special tools are given in
the back of this manual.
6Remove the o-ring; it will either be in the rotating seal
or on the shaft.
7Remove the six hex head bolts that hold the control
valve to the motor.
8 Lift the control valve away from the motor and
disengage the feedback linkage, see figure 9.
9Remove the control valve gasket.
10 Inspect the control valve: Start by thoroughly
flushing the control valve with clean solvent. Then blow
it dry with compressed air. Be sure to blow through all of
the control valve’s internal passages.
Inspect the control valve linkage. Move the control lever
back and forth; it should move freely without binding.
There should be no free play in the feedback link or
control lever.
Check the control valve orifice; if it is plugged after
flushing replace it.
Feedback
Linkage
Control Valve
Gasket
Figure 9
Major Repairs: Shaft Seal and Control Valve

12
11 Reposition the motor so the shaft is vertical and the
valve block is on top. Stand the motor on two blocks of
wood as shown in figure 10.
12 If the motor gets control pressure from the valve
block remove the control pressure hose and fittings.
13 Loosen the plugs and relief valves that are screwed
into the valve block.
14 Remove the four hex head bolts that hold the valve
block to the motor.
15 Remove the valve block.
16 Remove the two o-rings and back-up rings, and the
square cut seal from between the valve block and motor,
see figure 10.
17 Remove the low pressure relief valve (also called the
charge pressure relief valve).
Note: The low pressure relief valve can be identified by
the notches machined into its large hex head, see figure
11.
18 Mark the high pressure relief valves so they can be
reinstalled in the same ports.
Note: The three digit number stamped on each relief
valve indicates its pressure setting. Multiply this number
by ten to get the actual pressure setting (in PSI).
Examples:
20 Remove the o-rings and back-up rings from the relief
valves. The small o-ring on each high pressure relief
valve has a back-up ring on each side. The small o-ring
on the low pressure relief valve doesn’t have back-up
rings.
21 Inspect the relief valves for damage and replace as
necessary.
O-ring
High Pressure
Relief Low Pressure Relief
O-ring
Back-up
Rings
Notches
Figure 11
19 Remove the high pressure relief valves.
Number
Stamped on
Relief Valve Multiplier Relief Valve
Pressure
Setting
500 x10 5000 PSI
016 x10 160 PSI
Control
Pressure
Hose
Hose Fitting
Bolt (4)
Valve Block
Sq. Cut Seal
Back-up Ring
O-ring
Figure 10
Major Repairs: Valve Block

13
Shuttle Valve
Spring
Spool
Shuttle Valves
Shuttle Valve
Plug
Valve Block
Figure 13
Valve
Block Gauge Port
Plugs
Low Pressure
Relief Valve
High Pressure
Relief Valve
Figure 12
22 Remove the gauge port plugs and o-rings.
23 Remove the shuttle valve plugs and o-rings.
24 Remove the shuttle valve springs, spool, and valves.
25 Wash the relief valves, plugs, and shuttle valve in
clean solvent. Flush out the valve block. Blow dry the
parts with compressed air. Be sure to blow through the
internal passages of the valve block. Inspect the parts
for damage and replace as necessary.
26 Install the relief valves, shuttle valve, and plugs. Use
new o-rings and back-up rings.
Install back-up rings around the small o-rings on the high
pressure relief valves, see figure 11.
Lubricate the new o-rings with petroleum jelly before
installation.
Tighten all plugs and relief valves finger tight. They will
be torqued after the valve block is mounted on the
motor.
Major Repairs: Valve Block

14
Valve Plate
Bearing Plate
Dowel Pin (7)
Figure 14
27 Remove the end cover.
Caution: The cylinder barrel spring pre-load will
damage the motor’s internal parts if the end cover is
removed incorrectly.
Start by removing six of the eight bolts that hold the end
cover to the motor. Leave two bolts that are directly
across from each other tight.
Next, loosen the two remaining bolts one or two turns.
The end cover should rise as the bolts are loosened. If it
doesn’t tap it with a plastic hammer to break the gasket
seal.
After the gasket seal is broken loosen the bolts
gradually and evenly until the cylinder barrel spring pre-
load is relieved.
Remove the bolts and lift the end cover from the motor.
Be careful; do not drop the valve plate, it may lift away
with the end cover.
Important: Use care when handling the motor’s internal
parts. They are machined to extremely close tolerances.
28 Turn the end cover over and set it on a clean cloth.
Important: Always protect machined surfaces.
29 Remove the valve plate; it will either be on the end
cover or bearing plate.
Note: Keep track of the dowel pins, see figures 14 and
17. There is a total of seven dowel pins in the motor. It
is a good idea to put them in a small box so they don’t
get lost.
30 The bearing cup is slip-fit into the end cover. The
shims under the bearing cup adjust the shaft end play.
It is not necessary to remove these parts at this time.
31 Remove the bearing plate.
32 Remove the end cover gasket.
33 Remove the two dowel pins from cylinder barrel face.
Shims
Bearing
Cup
Major Repairs: End Cover and Servo Sleeves

15
34 Use a low clearance bearing puller to remove the
end cover bearing cone. Protect the cylinder barrel.
Note: A detailed drawing of the low clearance bearing
puller is given in the back of this manual.
Figure 15
Low Clearance
Bearing Puller
Scribe Marks 2
Servo Sleeve
O-rings
Servo Sleeve
Retainer
Figure 16
35 Mark the motor housing and servo sleeves so they
can reinstalled in the same locations.
36 Remove the servo sleeve retainers.
37 Scribe position marks on each servo sleeve; Make a
horizontal line where the servo sleeve and motor
housing meet. Then make a vertical line that starts on
the servo sleeve and ends on the housing, see figure 16.
These marks will indicate how far to screw the servo
sleeves in during reassembly.
38 Remove the servo sleeves.
39 Remove two o-rings from each servo sleeve.
Major Repairs: End Cover and Servo Sleeves

16
Bolt (12) Mounting Flange
Bearing Cup
Dowel
Pin
Gasket
Figure 17
40 Reposition the motor so the control valve mount is
on top. Be careful; do not let the cylinder barrel slide
out of the motor.
41 Remove the twelve hex head bolts that hold the
mounting flange to the motor.
42 Remove the mounting flange, tapping it with a
plastic hammer will help to break it loose.
43 Remove the mounting flange gasket.
Note: Do not remove the bearing cup from the mounting
flange unless it is damaged. Go to step 46 if the bearing
cup is undamaged.
44 Use an internal bearing puller or a long punch to
remove the old bearing cup. Be careful; do not damage
the mounting flange.
45 Press the new bearing cup into the mounting flange.
Be sure that it is pressed all the way to the bottom of the
recess.
Case Drain
Hole
Servo Pistons
Pin
Retaining Rings
Figure 18
46 Remove the inside retaining ring from each of the
pins that connect the servo piston links to the
swashplate. Slide the pins out through the case drain
holes and remove the servo pistons, see figure 18.
Note: Disassembly of the servo pistons is not required
unless they are damaged or the motor’s minimum
displacement is being changed.
Major Repairs: Mounting Flange, Servo Pistons and Trunnions

17
Sliding Hammer
Puller
Mark Trunnion
and Housing
Shims
O-ring
O-ring
Shims
Trunnion Bearing
Cone
Figure 19
47 Mark the motor housing and the trunnions so they
can be reinstalled in the same locations.
48 Repeat the following steps to remove each trunnion:
Remove the three hex head bolts that hold the trunnion
to the motor
The trunnion fits into the motor tightly; use a slide
hammer to loosen it. Screw the slide hammer into the
threaded hole in the trunnion. The sizes of the threaded
trunnion holes are listed below:
Remove the trunnions and shims.
Important: Keep the shims with each trunnion; they
must be reinstalled on the same trunnion during
reassembly. The shims pre-load the trunnion bearings.
Remove the o-ring from the trunnion, see figure 19.
49 If the trunnion bearings are damaged replace them.
A split blade bearing puller will be needed to remove the
bearing cone from the trunnion. Use a press to install
the new bearing cone.
50 Carefully remove the swashplate, cylinder barrel and
shaft through the mounting flange end of the housing.
Model Number Screw Size
33, 39, 46 3/8-16
54, 64 7/16-14
Major Repairs: Mounting Flange, Servo Pistons and Trunnions

18
Critical Sealing
Area
Figure 20
51 Remove the shaft and bearing assembly from the
swashplate and cylinder barrel. Keep the cylinder barrel
and pistons together.
Note: Do not remove the bearing cone from the shaft
unless it is damaged. Go to step 54 if the bearing cone
is undamaged.
52 Press the old bearing cone from the shaft.
Caution: Do not damage the sealing area of the shaft,
see figure 20. The shaft sealing area is between the
bearing journal and the key way or splined end of the
shaft. This area is extremely critical.
53 Press the new bearing cone onto the shaft. Use the
special stop limit tool shown in the back of this manual.
The position of the bearing cone on the shaft is
important.
Spacer
Retaining
Strap
Trunnion
Bearing Cup
Figure 21
Cylinder Barrel
Swashplate
54 Set the swashplate and cylinder barrel assembly on
the trunnion; in this position it will be easier to break the
retaining strap bolts loose. Remove one of the retaining
straps and loosen the other.
Important: keep the cylinder barrel and pistons
together.
55 Reposition the swashplate and cylinder barrel
assembly so the cylinder barrel is on the bottom.
Remove the swashplate by lifting it slightly and sliding it
over to disengage the retaining strap.
56 Remove the retaining strap and thrust plate from the
swashplate.
57 Replace the trunnion bearing cups if they are
damaged. Use a long punch to remove the old bearing
cups, then carefully press the new bearing cups into the
swashplate.
Major Repairs: Swashplate, Shaft and Cylinder Barrel

19
Reassembly
Inspect the cylinder barrel, pistons, piston slippers, and
thrust plate. Replace any worn or damaged parts.
Check all mating surfaces; replace any parts with
scratches or burrs that could cause leakage. Inspect
parts for excessive wear and replace as necessary.
Wash all metal parts in clean solvent and blow them dry
with compressed air. Do not wipe parts dry with paper
towels or cloth. Lint in a hydraulic system will cause
damage.
Always use new seals when reassembling hydraulic
motors. Refer to parts list 6-132 for seal part numbers,
replacement parts, and ordering information.
Important: During reassembly lubricate the new seals
with a petroleum jelly like Vaseline. Also lubricate all
machined surfaces and bearings with clean hydraulic
fluid.
Slipper Retainer
Plate
Retaining
Strap
Spacer
Piston
Swashplate
Piston Slipper
Thrust Plate
Figure 22
58 Before beginning reassembly check the piston
slipper clearance:
First, use a vernier calipers to measure the spacer
height, height “A” in figure 21.
Next, measure the thickness of the slipper retainer plate
and piston slippers, Thickness “B” in the figure.
Finally, calculate the piston slipper clearance “C” by
subtracting thickness “B” from height “A”.
Clearance “C” must not exceed .008 in. [,20 mm].
If the piston slipper clearance is too large replace worn
parts: the thrust plate and/or piston slipper assemblies.
Do not file or grind the spacers to adjust the slipper
clearance.
59 Position the cylinder barrel, pistons, and slipper
retainer so the piston slippers are on top.
60 Apply two drops of Loctite 271 in each of the four
retaining strap holes in the swashplate. Apply the
Loctite on closer than two threads from the running
surface. Do not apply loctitie to the retaining strap bolts.
Caution: Remove all excess Loctite, it will contaminate
the motor if not removed.
61 Place the thrust plate in the swashplate.
62 Install one of the retaining straps, and leave the bolts
loose.
63 Apply a light coating of clean hydraulic fluid to the
thrust plate.
64 Fit the swashplate onto the cylinder barrel assembly.
Be sure the slipper retainer plate is between the
swashplate and retaining strap.
65 Turn the swashplate and cylinder barrel over so the
swashplate is on the bottom.
66 Install the second retaining strap and tighten all four
retaining strap bolts to 18 lb-ft [25 Nm]. Remove all
excess Loctite.
67 Liberally lubricate the piston slippers, thrust plate,
retainer plate, pistons, and cylinders. These parts must
have sufficient start-up lubrication.
68 Slide the shaft and bearing assembly through the
swashplate into the cylinder barrel.
Swashplate
Thrust Plate
Slipper Retainer
Plate
Loctite Four
Threaded Holes
Figure 23
Bearing Cup
Retaining
Strap
Major Repairs: Swashplate, Shaft and Cylinder Barrel

20
Control Valve
Mount
Trunnion
O-ring
Shims
Shims
O-ring
Figure 24
72 Install the trunnion bolts and tighten them to the
specified torque given below:
69 Carefully, put the swashplate, cylinder barrel, and
shaft into the motor housing. Be sure the feedback
linkage is by the control valve mount.
70 Lubricate and install a new o-ring on each trunnion.
71 Install the trunnions and shims in their original
locations.
Strike the Trunnion to Free-up
Swashplate Movement
Spring
Compression
Scale
Model Number Trunnion Bolt Torque
33, 39 28 lb-ft [38 Nm]
46, 54, 64 44 lb-ft [60 Nm]
73 After the bolts are torqued strike one of the trunnions
to free up the swashplate’s movement.
74 Measure the swashplate breakaway force with a
spring compression scale. Attach the scale to the
feedback linkage as shown in figure 25. A swashplate
breakaway force of 2 to 5 lb [,9 to 2,3 Kg] is required.
Add or subtract trunnion shims as needed.
Figure 25
Important: The trunnion shims on
each side of the motor should be
equal thickness. The maximum
allowable difference between the
sides is .010 in. [,3 mm].
2
2
Major Repairs: Trunnions and Servo Pistons