Front-Wheel Steering Circuit (Right Turn) And Troubleshooting - JLG sky trak mmv Service Manual

Hydraulic System
9.8.15

Front-Wheel Steering Circuit (Right Turn) and Troubleshooting

(Refer to Section 9.8.31, Three-Mode Steering Circuit Descriptions for a more detailed explanation of this circuit.)
POWER
STEERING
UNIT
P
R
L T
OPERATOR'S CAB
Pressure
Return
Suction
Load Sense
Before troubleshoot-
ing any hydraulic cir-
cuit, 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.
9.58
HYDRAULIC
RESERVOIR
PUMP
CF PIL EF ACF ACR
ACCUMULATOR
CHARGE VALVE
LSG
P P1 SW DRAIN
If the steering is slow or difficult,
check the pressure at the "P1" port of
the accumulator charge valve.
If OK
Check that the check valve fitting at the
power steering unit is operating properly.
If OK
Check the power steering unit.
If OK
Check packing in steering cylinders.
T
a
DE
B
LS
Not
OK
Not
OK
Not
OK
Not
OK
FRONT AXLE
STEER
SELECT
P
VALVE
b
DE DE-ENERGIZED
DE
E ENERGIZED
A
REAR AXLE
Adjust/repair/replace pressure relief
valve on accumulator charge valve.
Replace check valve fitting.
Replace power steering unit.
Repair/replace cylinder(s).
Model MMV Rev. 12/04
MM3371