TM 5-3895-372-34
Section II.
REPAIR OF HYDRAULIC OIL PUMP
3-4.
Description. Pumps in this series are used to develop hydraulic fluid flow for the operation of mobile equipment.
The positive displacement pumping cartridges are of the rotary vane type with shaft side loads hydraulically balanced. The
flow rate depends on the pump size and the speed at which it is driven. The unit consists principally of an inlet cover, outlet
body, driveshaft and pumping cartridge.
3-5.
Preparation for Disassembly. The instructions contained in this section cover a complete disassembly,
inspection and assembly of the hydraulic pump. Sometimes a malfunction can be corrected without removing the pump
from the vehicle by replacing the cartridge assembly. This can be accomplished by removing the four housing screws and
removing the rear housing.
Drain all fluid from the pump and thoroughly clean the exterior surface. Prepare a clean, lint free surface on which to place
the internal parts for inspection and repair. Support the pump on blocks or clamp the body in a vise. If a vise is used, use
protective jaws to avoid damage to the body and its machined surfaces.
3-6.
Disassembly.
a.
Remove hydraulic oil pump. (See para 2-13.)
b.
Place pump body (9, fig. 3-1) in a vise to support during disassembly.
c.
Mark pump body (9) and cover (16) for proper alinement at assembly.
d.
Remove four bolts (17) from the cover (16) and remove.
e.
Remove two screws (19) and remove nameplate (18).
f.
Remove O-rings (13 and 15) and back-up ring (14) from pump body (9).
g.
Grasp the cartridge (12) and pull from pump body (9).
h.
Remove back-up ring (10) and packing (11) from cartridge (12).
i.
Remove lock ring (1) and shaft (4).
j.
Drive washer (6), seal (7) and wiper (8) from shaft end of pump body (9).
k.
Remove snap ring (2) and press shaft (4) from bearing (3) while supporting Inner race.
NOTE
Cartridge (12) is replaced only as an assembly.
3-7.
Clean and Inspect.
a.
Clean all parts in SD-2 drycleaning solvent.
b.
Inspect all parts for damage and replace as necessary.
3-8.
Assembly.
NOTE
Use a suitable seal installation tool to prevent damaging seal (7). Ensure the seal OD is below
the chamfer in pump body (9).
3-2
