Maintenance - Manitowoc Grove RT770E Service Maintenance Manual

RT770E SERVICE MANUAL

Maintenance

Troubleshooting
SYMPTOM
1. Erratic operation
o f e x t e n d i n g
t e l e s c o p i n g
cylinder.
2. Erratic operation
of retracting
telescoping
cylinder.
GROVE
PROBABLE CAUSE
a. Low hydraulic oil level.
b. Damaged relief valves.
c. Air in telescope cylinder.
d. Low engine rpm.
e. Lack of lubrication on boom sections.
f. Extremely tight boom
sheaves.
g. Improper boom alignment caused from
side loading.
h. Worn boom wear pads.
i. Distorted boom section.
j. Damaged telescope cylinder.
k. Clogged, broken, or loose hydraulic
lines or fittings.
l. Damaged control valve.
a. Low hydraulic oil level.
b. Damaged relief valve.
c. Air in cylinder.
d. Low engine rpm.
e. Lack of lubrication.
f. Check valve malfunctioning.
g. Improper boom alignment caused from
side loading.
h. Extremely tight boom retraction
sheave.
i. Distorted boom section.
j. Worn boom wear pads.
k. Bent cylinder rod(s).
l. Scored cylinder barrel.
m. Damaged piston seals.
n. Loose or damaged piston(s).
Published 11/26/2014, Control # 447-05
a. Check system for leaks. Make repairs as
needed. Fill reservoir.
b. Repair or replace relief valves.
c. Bleed by lowering telescope cylinder
below horizontal.
d. Increase engine rpm to recommended
setting.
e. Properly lubricate all boom sections.
extension f. Inspect and properly lubricate boom
extension sheaves.
g. Reduce and properly hoist load.
h. Replace wear pads and properly lubricate.
i. Replace distorted section.
j. Repair or replace cylinder.
k. Clean, tighten, or replace lines or fittings.
l. Repair or replace control valve.
a. Check system for leaks. Make repairs as
needed. Fill reservoir.
b. Repair or replace relief valve.
c. Bleed by lowering telescoping cylinder
below horizontal and cycle telescope
cylinder.
d. Increase engine rpm to recommended
setting.
e. Properly lubricate all boom sections.
f. Repair or replace check valve.
g. Reduce and properly hoist load.
h. Inspect and properly lubricate.
i. Replace distorted section.
j. Replace wear pads and properly lubricate.
k. Replace cylinder rod(s) and all cylinder
seals.
l. Repair or replace cylinder barrel.
m. Replace all cylinder seals.
n. Replace all seals and re-torque or replace
piston(s).
BOOM
SOLUTION
4
4-39