JLG sky trak mmv Service Manual page 438

Hydraulic System
Accumulator Charge Troubleshooting (cont'd)
Problem
4. Accumulator fails to start
charging
5. Very rapid cycling of
accumulator charging valve
6. Lack of adequate flow
through accumulator charge
valve
9.140
Cause
1. No oil or low oil level in hydraulic
reservoir.
2. Pump worn or inoperative and
not delivering full flow or
pressure.
3. Air in accumulator line.
4. Inoperative accumulator
charging valve.
1. Incorrect settings of
accumulator gas charge.
2. Inoperative accumulator
charging valve.
1. Pump worn or inoperative and
not delivering full flow or
pressure.
2. Inoperative relief valve in
accumulator charge valve.
3. Inoperative accumulator
charging valve.
Remedy
1. Check oil level and add oil as
needed.
2. Check pump flow and pressure.
Refer to Section 9.7, Hydraulic
System Testing .
3. Bleed accumulator line.
4. Replace accumulator charging
valve.
1. Check accumulator gas charge.
Refer to Section 9.13.2, Pre-
Charging Accumulator .
2. Replace accumulator charging
valve.
1. Check pump flow and pressure.
Refer to Section 9.7, Hydraulic
System Testing .
2. Check relief valve setting. Refer
to Section 9.7, Hydraulic
System Testing .
3. Replace accumulator charging
valve.
Model MMV Rev. 12/04