Manitowoc Grove RT770E Service Maintenance Manual

4-39
Published 11/26/2014, Control # 447-05
RT770E SERVICE MANUAL BOOM
4
GROVE
Maintenance
Troubleshooting
SYMPTOM PROBABLE CAUSE SOLUTION
1. Erratic operation
of extending
telescoping
cylinder.
a. Low hydraulic oil level. a. Check system for leaks. Make repairs as
needed. Fill reservoir.
b. Damaged relief valves. b. Repair or replace relief valves.
c. Air in telescope cylinder. c. Bleed by lowering telescope cylinder
below horizontal.
d. Low engine rpm. d. Increase engine rpm to recommended
setting.
e. Lack of lubrication on boom sections. e. Properly lubricate all boom sections.
f. Extremely tight boom extension
sheaves.
f. Inspect and properly lubricate boom
extension sheaves.
g. Improper boom alignment caused from
side loading.
g. Reduce and properly hoist load.
h. Worn boom wear pads. h. Replace wear pads and properly lubricate.
i. Distorted boom section. i. Replace distorted section.
j. Damaged telescope cylinder. j. Repair or replace cylinder.
k. Clogged, broken, or loose hydraulic
lines or fittings.
k. Clean, tighten, or replace lines or fittings.
l. Damaged control valve. l. Repair or replace control valve.
2. Erratic operation
of retracting
telescoping
cylinder.
a. Low hydraulic oil level. a. Check system for leaks. Make repairs as
needed. Fill reservoir.
b. Damaged relief valve. b. Repair or replace relief valve.
c. Air in cylinder. c. Bleed by lowering telescoping cylinder
below horizontal and cycle telescope
cylinder.
d. Low engine rpm. d. Increase engine rpm to recommended
setting.
e. Lack of lubrication. e. Properly lubricate all boom sections.
f. Check valve malfunctioning. f. Repair or replace check valve.
g. Improper boom alignment caused from
side loading.
g. Reduce and properly hoist load.
h. Extremely tight boom retraction
sheave.
h. Inspect and properly lubricate.
i. Distorted
boom section. i. Replace distorted section.
j. Worn boom wear pads. j. Replace wear pads and properly lubricate.
k. Bent cylinder rod(s). k. Replace cylinder rod(s) and all cylinder
seals.
l. Scored cylinder barrel. l. Repair or replace cylinder barrel.
m. Damaged piston seals. m. Replace all cylinder seals.
n. Loose or damaged piston(s). n. Replace all seals and re-torque or replace
piston(s).

Manitowoc Grove RT770E Specifications

General

Brand	Manitowoc
Model	Grove RT770E
Category	Construction Equipment
Language	English