8
Model 72400
Disassembly
8
Remove housing gasket from housing or endcover.
9
With pump still in vise, remove the six cap screws retaining
the manual servo control assembly. Remove the control
assembly and control housing gasket from the housing.
Remove orifice plates, noting location for reassembly. Remove
nut and lock washer from control arm, remove arm. Note
position of control arm for reassembly.
Refer to Appendix B for disassembly and Inspection of control
assembly.
10 To remove rotating kit assembly from housing, first
remove pump from vise holding the rotating kit assembly in
position. Lower pump so that the shaft end (flange end) is up.
Set the rear of housing onto table with housing flat and rotating
kit assembly at rest on table. (Hole in table, for protruding
shaft, is required.) Lift and remove the housing and shaft from
rotating kit assembly, and swashplate.
11 Remove swashplate from rotating kit assembly and servo
piston follower from swashplate.
Refer to Appendix C for disassembly and Inspection of rotating
kit.
Swashplate Inspection:
• The finish on the piston shoe surfaces of the swashplate
should show no signs of scoring.
• Inspect swashplate bushing surface for wear and surface
for coating transfer from bushing.
12 To remove servo piston assembly from housing, start with
the four each cap screws and washers retaining each cover
plate.
13 In removing the cover plate from the servo piston bolt,
remove jam nut, washer, and seal washer. Hold the servo
piston bolt with hex key and unscrew cover plate off of bolt.
14 Remove servo piston assembly and seal sub-assemblies
(two sets) from housing. Note: Disassembly of servo piston
assembly is not required.
15 Remove retaining ring from the front of housing. Press the
shaft, shaft seal or spacer, and washer from housing. Remove
retaining ring, thrust washer, thrust bearing, second thrust
washer, and second retaining ring from shaft.
Disassembly -
Servo Controlled Piston Pump
The following instructions apply to a single servo controlled
piston pump with or without a gerotor charge pump. A tandem
pump assembly should be separated into individual pumps
before disassembly.
1
Position the pump into a protected jaw vise, clamping onto
the outer portion of the flange, with the cap screws up. Mark the
relationship of the working ports (for reassembly identification)
to the servo control assembly with a scribe. Remove the four
cap screws retaining endcover.
No gerotor charge pump skip to step 6.
2
Lift the charge pump adapter assembly straight up off
endcover, shaft, and gerotor. Gerotor may stay in adapter or on
endcover.
3
Remove o-ring from charge pump adapter.
4
Remove outer gerotor ring from either the charge pump
adapter or the inner gerotor ring.
Refer to Appendix A for disassembly and inspection of charge
pump adapter assembly.
5
Remove the inner gerotor ring and key from drive shaft or
inner gerotor ring and coupler assembly from shaft.
6
Lift endcover straight up off shaft and housing. Remove
valve plate from endcover or from rotating kit assembly, still in
housing.
7
From endcover, remove bypass valve or plug, and relief
valve assemblies. Note: Mark the relief valve in relationship to
the cavity it was removed, for reassembly purposes.
Endcover Inspection:
• Check the bearing (press fit) in endcover. If needles
remain in cage, move freely, and setting is at the dimension
shown in figure 1-3, removal not required.
• Check roll pin in endcover. If tight and set to the
dimension shown in figure 1-3, removal not required.
4,39 mm
[.173 in.]
2,29 mm
[.09 in.]
Numbered End
Figure 1-3
