Allied Systems W8L Service Manual page 79

PROBLEM
Operation is rough or not
regular.
Low oil pressure.
Brake does not release
or winch stalls during low
RPM shift.
Figure 3-20 Troubleshooting Analysis Check Chart for Service Personnel
POSSIBLE CAUSE
Low oil pressure.
Wrong oil.
Accumulator malfunction.
Hydraulic system suction leaks.
Observe oil exiting lube valve while
tractor is operating. Suction leaks will
cause oil to foam.
Brake pressure fl uxuates, air in valve,
orifi ce missing from brake dump fi t-
ting (last used on S/N AW8L-3129).
Leaking pressure hoses and fi ttings. Check for leaks and replace components where
Defective or improperly adjusted oil
relief valve; poppet may be stuck
open.
Oil brake leaking internally (indicated
by low brake pressure).
Defective hydraulic pump.
Low oil pressure.
Accumulator system malfunction.
Brake dump valve malfunction.
Damaged brake piston, piston hous-
ing or seal rings.
Low clutch pressure or low oil pump
volume.
CORRECTION
Do Oil Pressure Test in Service subsection, and see
the item of Low Oil Pressure on this page.
Drain oil and replace with correct grade. Refer to
Figure 1-10 for the
Recommended
Check accumulator and recharge/replace as neces-
sary.
Check the following for air leaks:
1. Suction hose to pump connection.
2. Pump shaft seal.
3. Suction fi lter cover and gasket.
4. Suction hose for cracks or collapsed sections.
necessary. Be sure hoses are not rubbing on any
gears or winch components.
Clean relief valve if no pressure, then adjust. Check
relief valve with pressure gauge. Replace if defective.
Repair as required.
Check pump pressure output only after all other
checks have been made. Worn pump indicated by
pressure variation with engine RPM. If pump is at
fault, replace.
Refer to "Low Oil Pressure" troubleshooting item
above.
Check for:
1. Proper leakdown time as described in Figure 3-18.
2. Leaking accumulator valve.
3. Leak in accumulator lines.
4. Damaged or defective accumulators.
Check for proper operation.
Check piston and piston housing cavity for damage.
Replace if scored or broken. Always replace seals
when brake is repaired.
Refer to "Low Forward or Reverse Clutch Pressure"
troubleshooting item below.
Section 3
Oil List.
(Continued on next page)
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