JLG sky trak mmv Service Manual page 317

Before troubleshooting any
hydraulic circuit, ALWAYS
begin by checking the
following:
1. Hydraulic oil level in the
reservoir
2. All hoses, tubes, fittings
for leaks, kinks,
interference, etc.
3. Air in the lines
NOTE:
When checking pressures in
circuits, refer to Section 9.7,
Hydraulic System Testing for
correct pressure readings.
Model MMV Rev. 12/04
If park brake fails to release
with park brake release
hand pump, check hand
pump
If OK
Check for external
leaks,loose fittings or lines
If OK
Within the front axle:
If not releasing, check the
piston seals.
Hydraulic System
Not
Replace hand pump.
OK
Tighten fittings or lines, or
Not
replace fittings or lines
OK
Refer to ZF Axle Repair
Manual, Model MS-T 3060,
Not
ZF part number 5871 560 002.
OK
JLG part # 8990430
9.19