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Published 10/19/2017, Control # 618-00
GRT880 SERVICE MANUAL BOOM
Removal And Installation
Removal and installation of the telescope cylinder from the
boom is described under disassembly and assembly of the
boom found in this same section.
Disassembly And Assembly
Disassembly and assembly procedures of the telescope
control valve is provided in Valves, page 2-39.
3. Telescope
cylinder will not
extend.
a. Low hydraulic oil level. a. Check system for leaks. Make repairs as
needed. Fill reservoir.
b. Relief valve malfunctioning. b. Repair or replace relief valve.
c. Excessive load. c. Reduce load.
d. Clogged hose and fittings. d. Replace hose or fittings. (Refer to
Manitowoc Crane Care Parts Manual).
e. Broken valve spool. e. Replace valve.
f. Damaged piston seals. f. Replace all cylinder seals.
g. Damaged piston(s). g. Replace piston(s) and all cylinder seals.
h. Bent boom section(s). h. Replace damaged boom section(s).
i. Broken hydraulic pump coupling. i. Replace broken hydraulic pump coupling.
j. Worn or damaged hydraulic pump
section.
j. Repair or replace pump section.
4. Telescope
cylinder will not
retract.
a. Low hydraulic oil level. a. Check system for leaks. Make repairs as
needed. Fill reservoir.
b. Relief valve damaged. b. Repair or replace relief valve.
c. Excessive load. c. Reduce load. (Refer to load chart).
d. Inoperative check valve. d. Replace check valve.
e. Clogged hose and fittings. e. Replace hose or fittings. (Refer to
Manitowoc Crane Care Parts Manual).
f. Broken valve spool. f. Replace valve section.
g. Broken piston(s). g. Replace piston(s) and all cylinder seals.
h. Damaged piston seals. h. Replace all cylinder seals.
i. Bent boom section(s). i. Replace damaged boom section(s).
j. Broken hydraulic pump coupling. j. Replace broken hydraulic pump coupling.
k. Worn or damaged hydraulic pump. k. Repair or replace pump.
l. Broken
hydraulic pump shaf
t. l. Replace pump shaft.
SYMPTOM PROBABLE CAUSE SOLUTION
Reference Only
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