Jacobsen HR5111 Service And Repair Instructions page 175

TRACTION SYSTEM
TRACTION PUMP TEST (See Figure 8R-11)
1. Raise front wheels off the ground.
2. Remove 4 wheel drive hose from the left side of
the traction pump, cap tee and plug line.
3. Remove front traction motor hose from left side of
traction pump.
4. Remove front traction motor hose from right side
of traction pump.
5. Plug front motor hoses.
6. Install tee fittings to each side of traction pump.
7. Connect IN port of tester to left side of traction
pump, cap tee.
8. Connect OUT port of tester to right side of traction
pump, cap tee.
9. Open tester load valve, start engine, advance throt-
tle to 2800 engine rpm.
10. Read/record charge pressure.
•
If the charge pressure is not within 190–250 psi,
replace the charge relief valve cartridge (see
Section 8K).
•
If charge pressure is not affected after changing
the charge relief cartridge, proceed with an in-
strument test, implement pump section 4.
11. Slowly close tester load valve until 3000 psi is
obtained and allow oil to heat up to 150°F.
12. Open tester load valve.
13. Push traction pedal to obtain 10 gpm. Record no
load gpm flow.
14. Slowly close tester load valve until 3000 psi is
obtained.
15. Read/record gpm flow. Record engine rpm. Sub-
tract gpm flow from 10 gpm NO LOAD flow.
•
If flow drops 1 gpm or less, pump is okay.
•
If flow drop is 1-1/2 gpm, pump is marginal.
•
If flow drops more than 1-1/2 gpm pump has
excessive internal leakage.
16. Continue closing load valve, read/record psi when
flow drops off. This is the forward traction loop
relief valve setting.
CAUTION
DO NOT exceed 4000 psi during this test.
•
If the relief valve opens at 3500 psi, relief is
okay.
•
If relief pressure is above or below 3500 psi, re-
place the relief valve on the left side of the hy-
drostatic pump.
SECTION 8R. INSTRUMENT TEST
Figure 8R-11. Traction Pump Test
8R-11
HYDRAULICS
8R