Hyster D174, Service & Repair Manual

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Hydraulic Gear Pump Repair 1900 SRM 97
1. CAPSCREW (4)
2. GEAR HOUSING
3. PIN (4)
4. DRIVE GEAR
5. DRIVEN GEAR
6. KEY (2)
7. THRUST PLATE (2)
8. PLASTIC GASKET (2)
9. PAPER GASKET (2)
10. SEAL (2)
11. BODY
12. GEAR HOUSING
13. DRIVE GEAR AND SHAFT
14. DRIVEN GEAR AND SHAFT
15. SPRING
16. BALL
17. FRONT COVER
18. SEAL
Figure 9. Hydraulic Gear Pump Tandem
7. Look for damage on seals. Replace all seals and
O-rings, even if they are in good condition. Look
for cuts or changes in shape that can cause dam-
age. Find out what damage caused the pump
to fail. A damaged seal for the thrust plate can
cause the shaft seal to leak. A damaged shaft
seal can cause air to enter the hydraulic system.
8. Inspect flow control valve and relief valve for dirt
or scratches. Make sure piston moves freely in
the bore. Look at poppet and seat for damage.
The springs must not be broken or bent. Inspect
O-rings for damage. Make sure orifices are open.
CAUTION
Do not permit dirty oil to enter the gear pump.
9. If any parts of the pump have damage from dirt
in the oil, inspect hydraulic tank. Drain tank,
clean screen and tank, and replace filter.
10. Inspect inlet hose to the gear pump. Use a lamp
to look inside the hose. Look for pieces of rubber
that are separating from the hose. Inspect hose
for restrictions at bends. Check for loose fittings
or damaged O-rings.
ASSEMBLE
CAUTION
Make sure no dirt enters the pump during as-
sembly.
1. Lubricate all parts with hydraulic oil before they
are installed into the pump.
2. Put Loctite 290
®
sealant around outside of front
seal. Install seal in front cover. Make sure seal
is installed straight. If pump has a ball bearing
for the shaft, install it in the front cover. Install
snap rings.
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