Rear Steering System; Troubleshooting - Manitowoc Grove RT880E Service And Maintenance Manual

RT880E SERVICE MANUAL
Functional Check
A normal periodic functional check of the entire steering
system will generally be adequate to ensure satisfactory
service.
1. Check all fittings for leakage. An accumulation of moist,
black dirt is a good indication of leakage.
2. With the engine running at idle and at full throttle, and
with the machine standing still and moving, turn the
steering wheel through the full range of travel. Note any
speed irregularities and sticky sensation. This may indi-
cate dirt in the fluid. If the steering wheel continues to
rotate when started and released, a condition known as
Motoring exists. This may also indicate dirty fluid in the
system.

REAR STEERING SYSTEM

Troubleshooting

Symptom
1. Rear steering inoperative.
2. Hard to steer left and right.
3. Steering is erratic left and right.
Grove
3. Ensure the system has adequate power. If there is an
indication of hard steering, this can be caused by either
a reduced oil flow to the control valve or a reduced sys-
tem relief pressure. Adequate oil flow under all condi-
tions can best be checked by timing the full travel of the
cylinder with the steered axle unloaded and loaded. If
there is a great difference at low engine speed and slight
difference at high engine speeds this may indicate a
defective pump. Adequate oil pressure can only be
determined by connecting a pressure gauge [3500 psi
(24 MPa) full scale recommended] at the swing/steer/
pressure gauge test port (GP2). With the engine running
at a medium speed, turn the steering wheel to one end
of the travel and hold the cylinders at the travel limit
briefly, just long enough to read the pressure gauge.
Never hold the system at relief pressure for more than a
few seconds at a time. The pressure gauge should indi-
cate 2600 psi (17.9 MPa).
Probable Cause
a. Hydraulic oil low.
b. Clogged, broken, or loose
hydraulic lines or fittings.
c. Steer cylinder locked.
d. Defective control valve.
e. Defective steer cylinder(s).
f. Lack of electrical signal
a. Hydraulic oil low.
b. Clogged or loose hydraulic
lines or fittings.
c. Defective steering
valve.
d. Defective hydraulic pump.
e. Clogged or loose hydraulic
lines or fittings.
f. Defective steer cylinder.
g. Damaged relief.
a. Hydraulic oil low.
b. Clogged or loose hydraulic
lines or fittings.
c. Defective steering
valve.
d. Defective hydraulic pump.
Published 11-10-2014, Control # 524-00
UNDERCARRIAGE
Solution
a. Refill hydraulic reservoir.
b. Clean, tighten, or replace
lines or fittings.
c. Repair or replace cylinders.
d. Repair or replace valve.
e. Repair or replace cylinder(s).
f. Check electrical connections/
wiring
a. Refill hydraulic reservoir.
b. Clean or tighten lines or
fittings.
control c. Repair or replace valve.
d. Repair or replace pump.
e. Clean or tighten lines or
fittings.
f. Repair or replace cylinder.
g. Replace relief valve.
a. Refill hydraulic reservoir.
b. Clean or tighten lines or
fittings.
control c. Repair or replace valve.
d. Repair or replace pump.
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