HYDROSTATIC POWER TRAIN
4203781 First Edition 5-35
5
Figure 5-23
4. Connect flow meter inlet test hose (5) to fitting (2).
5. Connect flow meter outlet test hose (3) to hose (1).
6. Open flow meter valve (4) completely.
Figure 5-24: Charge Pump Test
7. Set park brake.
NOTE
Verify engine rpm is within specification (2800 rpm ± 50)
to ensure accurate hydraulic test results.
8. Start engine and run at full throttle (2800 rpm ± 50).
!
CAUTION
9. Use the flow meter to warm the hydraulic oil. Turn the
flow meter valve (4) until a reading of 750 psi (52 bar)
or one half of the relief valve rating is reached. Warm
oil to 120–150° F (49–65° C).
10. Open flow meter valve (4) completely. Read and
record the charge pump no load flow.
11. Slowly close flow meter valve (4) until pressure
reaches 1125 psi (78 bar). Read and record the
charge pump loaded flow.
12. Open flow meter valve (4) and stop engine.
13. Calculate charge pump leakage.
(Step 10 – Step 11 / Step 10 x 100 = Leak
Percentage)
Is charge pump leakage 10% or less?
YES The charge pump is good. Proceed to
step 14.
NO Proceed to next question.
Is charge pump leakage 11% to 20%?
YES The charge pump is marginal. Additional
testing is required. (See “Field Test
Procedures” on page 6-24.)
NO Proceed to next question.
Is charge pump leakage 21% or more?
YES Repair or replace charge pump. (See “Gear
Pump” on page 6-58.)
14. Disconnect and remove test equipment. Install all
hoses and fittings as noted prior to removal.
15. Install and connect all components as noted prior to
test.
16. Check hydraulic oil level. Add oil as needed. (Refer to
“Safety, Operation, and Maintenance Manual” for
correct oil specifications.)
5
TN1359
4
3
TN2255
TN2255
Do not exceed 1500 psi (103 bar) as this test does
not utilize system relief.
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