Manitowoc Grove RT9130E-2 Service And Maintenance Manual page 195

RT9130E-2 SERVICE MANUAL
Symptom
3. Boom raises
slowly.
4. Boom lowers
slowly.
5. Boom will not raise.
Grove
Probable Cause
a. Low hydraulic oil level.
b. Low engine rpm.
c. Damaged relief valve.
d. Extremely cold hydraulic oil.
e. Improper hose or fittings, installed.
f. Operating two functions in the same
control valve bank assembly.
g. Restriction in return hose.
h. Cylinder piston seals leaking.
i. Scored cylinder barrel.
j. Worn hydraulic pump section.
a. Low hydraulic oil level.
b. Low engine rpm.
c. Damaged relief valve.
d. Operating two functions within the
same control valve bank assembly.
e. Extremely cold hydraulic oil.
f. Improper hose or fittings installed.
g. Restriction in return hose.
h. Cylinder piston seals worn.
i. Scored cylinder barrel.
j. Worn hydraulic pump section.
k. Piston rod broken (loose from piston).
a. Low hydraulic oil.
b. Main relief valve or circuit relief valve
damaged.
c. Excessive load.
d. Worn or damaged hydraulic pump
section.
e. Broken pump shaft.
f. Broken pump drive coupling.
g. Broken control valve spool.
Published 11-22-2016, Control # 345-12
Solution
a. Check system for leaks. Make repairs
as needed. Fill reservoir.
b. Increase and maintain engine rpm.
c. Repair or replace relief valve.
d. Operate unit to bring oil to operating
temperature.
e. Replace hose or fittings. Refer to your
Manitowoc Crane Care Parts Manual.
f. Feather controls to obtain desired
speed of both functions.
g. Replace return hose.
h. Replace all cylinder seals.
i. Hone or replace barrel.
j. Repair or replace pump section.
a. Check system for leaks. Make repairs
as needed. Fill reservoir.
b. Increase rpm to recommended level.
c. Repair or replace relief valve.
d. Feather controls to obtain desired
speed of both functions.
e. Operate unit to bring oil to operating
temperature.
f. Replace hose or fittings. Refer to your
Manitowoc Crane Care Parts Manual.
g. Replace return hose.
h. Replace all cylinder seals.
i. Hone or replace barrel.
j. Repair or replace pump section.
k. Replace piston rod and all cylinder
seals.
a. Check system for leaks. Make repairs
as needed. Fill reservoir.
b. Repair or replace relief valve.
c. Reduce load as required.
d. Repair or replace pump section.
e. Replace pump shaft and seals.
f. Replace drive coupling.
g. Replace control valve.
BOOM
4
4-33