Maintenance - Manitowoc Grove RT770E Service Maintenance Manual

UNDERCARRIAGE

Maintenance

Front Steering System
Troubleshooting
Table 8-1
Symptom
1. Hard to steer left and
right.
2. Hard to steer either left
or right.
3. Steering is erratic left
and right.
4. Noisy hydraulic pump
caused by cavitation.
5. Hydraulic pump shaft
seal
leakage.
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
8-8
Probable Cause
a. Hydraulic oil low.
b. Clogged or loose hydraulic lines or
fittings.
c. Defective flow divider valve(s).
d. Defective steering control valve.
e. Defective hydraulic pump.
a. Clogged or loose hydraulic lines or
fittings.
b. Defective steer cylinder.
a. Hydraulic oil low.
b. Clogged or loose hydraulic lines or
fittings.
c. Defective steering control valve.
d. Defective hydraulic pump.
a. Hydraulic oil low.
b. Suction line plugged or too small.
a. Worn shaft seal.
NOTE: If replacing the shaft seal does not
stop leakage, the pump should be
disassembled and checked for the
following:
b. Broken diaphragm seal or backup
gasket.
c. Bearing out of position.
d. Excessive internal wear.
Published 11/26/2014, Control # 447-05
a. Check system for leaks. Make
repairs as needed. Fill reservoir.
b. Clean or tighten lines or
fittings.
c. Repair or replace valve(s).
d. Repair or replace valve.
e. Repair or replace pump.
a. Clean or tighten lines or
fittings.
b. Repair or replace cylinder.
a. Check system for leaks. Make
repairs as needed. Fill reservoir.
b. Clean or tighten lines or
fittings.
c. Repair or replace valve.
d. Repair or replace pump.
a. Refill hydraulic reservoir. Refer to
Lubrication, page 9-1.
b. Clean line and check for size.
a. Replace shaft seal.
b. Replace seal or gasket. Refer to your
M a n i t o w o c C r a n e C a r e P a r t s
Manual.
c. Replace bearing.
d. Replace pump.
steering wheel through the full range of travel. Note any
speed irregularities and sticky sensation. This may
indicate 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.
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
RT770E
Solution