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GENERAL INFORMATION
The hydraulic check-out procedure is intended to help
the technician check, adjust, and diagnose problems
in the steering and hoist circuits. The technician should
read the entire check-out procedure prior to performing
any steps to become familiar with the procedures and
all the warnings and cautions. The check-out proce-
dure begins by checking the basic system before
checking individual components.
Included on the last page is a data sheet to record the
information observed during the hydraulic system
check-out procedure. The data sheet is designed to be
removed, copied, and used during the check-out pro-
cedure.
* Steps indicated in this manner should be re-
corded on the data sheet for reference.
Hydraulic fluid escaping under pressure can have
sufficient force to enter a person's body by pene-
trating the skin and cause serious injury, and pos-
sibly death, if proper medical treatment by a
physician familiar with this type of injury is not
received immediately.
Before disconnecting pressure lines, replacing
components in the hydraulic circuits, or installing
test gauges, ALWAYS bleed down hydraulic steer-
ing accumulator.
The steering accumulators can be bled down by
shutting down the engine, turning key switch
"Off", and waiting 90 seconds. Confirm the steer-
ing pressure is released by turning the steering
wheel; no front wheel movement should occur.
Bleed down brake system accumulators prior to
removing any hoses supplying oil to the brake
system.
The AC drive system Rest Switch, located on the
instrument panel, must be in the ON position and
the GF Cutout Switch in the CUTOUT position
during test procedures. (See Figure 3-1, page E3-2,
Propulsion System, for GF switch location.)
L10012
HYDRAULIC CHECK-OUT PROCEDURE
Hydraulic Check-out Procedure
STEERING CIRCUIT CHECK-OUT &
ADJUSTMENT PROCEDURE
The steering circuit hydraulic pressure is supplied from
the piston pump and steering accumulators. Some
steering system problems, such as spongy or slow
steering or abnormal operation of the "Low Steering
Pressure" warning light can sometimes be traced to
internal leakage of steering components. If internal
leakage is suspected, refer to "Steering Circuit Com-
ponent Leakage Test."
NOTE: Excessive internal leakage within the brake
circuit may contribute to problems within the steering
circuit. Be certain that brake circuit leakage is not
excessive before troubleshooting steering circuit. For
Brake Circuit Test Procedure, refer to Section "J",
Brake System.
The steering circuit can be isolated from the brake
circuit by releasing all steering system pressure and
then releasing all pressure from the brake accumula-
tors and removing the brake system supply line (4,
Figure 10-2) from the bleeddown manifold (see
WARNING). Plug the brake supply hose and cap the
fitting at the bleeddown manifold to prevent high pres-
sure leakage.
Prior to checking the steering system, the hydraulic
steering and brake systems must have the correct
accumulator precharge and be up to normal operating
temperatures. Refer to "Steering Circuit Component
Repair, Steering Accumulator Charging Procedure" in
this section of the manual for accumulator charging
instructions.
If the steering and brake pump has just been in-
stalled, it is essential that the steering pump case
is full of oil prior to starting the engine. Refer to
"Steering Circuit Component Repair, Steering and
Brake Pump", Section L6 for instructions.
L10-1
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Troubleshooting
