JLG sky trak mmv Service Manual page 361

If there is no steering, check the
steering system electrical
Check the pressure at the "P1" port of the
accumulator charge valve.
Check that the check valve fitting at the
power steering unit is operating properly.
Check the power steering unit.
Check the front and rear steering cylinders
Front or rear wheels are not parallel
in front or four-wheel steering mode.
Check the steer select valve.
Check packing in steering cylinders.
If there is no four-wheel or crab
steering, check the steer select valve.
Check the steer select switch and wiring.
Model MMV Rev. 12/04
components.
If OK
If OK
If OK
If OK
for packing leaks.
If OK
Check pump flow.
If OK
Check wheel alignment.
If OK
If OK
If OK
Refer to the steering circuits and
components in Section 10.7, Electrical
Not
OK System Troubleshooting and Section
10.13, Switches and Solenoids.
Adjust/repair/replace the pressure relief
Not
OK valve.
Not
Replace check valve fitting.
OK
Not
Replace power steering unit.
OK
Not
Repair/replace steering cylinder(s).
OK
Not
Repair/replace pump.
OK
Not
Perform indexing procedure on vehicle.
OK
Refer to ZF Axle Repair Manuals:
(Front) Model MS-T 3060,
ZF part number 5871 560 002
Not
JLG part number 8990430
OK
(Rear) Model MS-T 3045,
ZF part number 5871 550 002
JLG part number 8990419
Not
Replace the steer select valve.
OK
Not
Repair/replace cylinder.
OK
Inspect/replace the
Not
OK steer select valve.
Refer to the steering circuits and
components in Section 10.7, Electrical
Not
System Troubleshooting and Section
OK
10.13, Switches and Solenoids.
Hydraulic System
9.63