Troubleshooting - Manitowoc Grove 5540F Service Manual

STRUCTURALS

Troubleshooting

.
Trouble
A - The winch will not lower the load or
not lower the load smoothly.
B - Oil leaks from vent plug.
11-50
Possible Cause
1. The friction brake may not be
releasing as a result of a defective
brake cylinder seal.
NOTE: If the brake cylinder seal is
defective leaking will occur
from the winch vent plug.
2. Friction brake will not release as a
result of damaged brake disc.
1. Same as A2.
2. Motor seal my be defective as a
result of high system
pressure.
5540F/YB5515 SERVICE MANUAL
Remedy
1. 1.Check brake cylinder seal as
follows:
a. Disconnect the swivel tee
f r o m t h e b r a k e r e l e a s e
port.Connect a hand pump
with an accurate 0-2000 psi
( 0 - 1 3 7 9 0 k P a ) p r e s s u r e
gauge and shut-off valve to
fitting in the brake release
port.
a. Apply 1000 psi (6895 kPa) to
the brake. Close the shutoff
valve and let stand for five (5)
minutes.
a. If there is any loss of pressure
in five (5) minutes, the brake
c y l i n d e r
disassembled for inspection
o f s e a l i n g s u r f a c e s a n d
replacement of the seals.
R e f e r t o " M o t o r S u p p o r t -
Brake Cylinder Service".
2. Disassemble the brake to inspect
brake discs.
height as described in "Motor
Support-Brake Cylinder Service."
1. Same as A2.
2. System back pressure must not
back exceed 500 psi (3448 kPa).
Inspect hydraulic system for a
restriction in the return line from
the main control valve to the
hydraulic tank.
Oil analysis
contamination has worn the motor
shaft and seal. Install a new motor
seal.
s h o u l d b e
Check stack-up
may indicate