BOOM GRT880 SERVICE MANUAL
4-58
Published 10/19/2017, Control # 618-00
Lift Cylinder Removal
1. Extend and set the outriggers and level the crane.
2. Elevate the boom slightly so that the lift cylinder is
extended approximately 1 ft (0.3 m).
3. Ensure the boom is fully supported by placing blocking
or cribbing under the boom. Rest the boom on the
blocking or cribbing.
NOTE: Refer to Figure 4-132 and Figure 4-133 for removal
and installation of lift cylinder.
NOTE: Lift cylinder weighs 1100 kg(2425 lb).
4. Attach an adequate lifting/supporting device to the lift
cylinder.
5. Remove the capscrews, washers, and end plate
securing the upper lift cylinder shaft to the side of the
attachment fitting on the boom. Loosen the set screws
on the opposite side.
6. Remove the capscrews, lock washers, flat washers, and
end plate securing the lift cylinder lower pivot shaft to the
turntable.
7. Remove the upper lift cylinder shaft, spacers, and shims,
noting position of each. Activate the hydraulic system
and retract the lift cylinder enough to clear the upper
attach point.
8. Tag and disconnect all the hydraulic lines to the cylinder.
Cap or plug all openings with high pressure fittings.
9. Remove the lower lift cylinder shaft and spacers, noting
position of each.
10. Move the lift cylinder to a clean work area.
Lift Cylinder Installation
NOTE: Refer to Figure 4-132 and Figure 4-133 for removal
and installation of lift cylinder.
NOTE: Lift cylinder weighs 1100 kg(2425 lb).
1. Attach an adequate lifting device to the lift cylinder and
position the cylinder over the attach fitting on the
turntable.
2. Lower the lift cylinder into the attach fittings on the
turntable and align the lift cylinder bushing with the
attach fitting holes.
3. Install the lift cylinder lower pivot shaft and spacers
following positions noted during disassembly.
4. Secure pivot shaft in place using end plate, flat washers,
lock washers, and capscrews.
5. Connect the extend and retract hoses, as tagged during
disassembly, to the lift cylinder.
6. Activate the crane’s hydraulic system and align the lift
cylinder rod end with the attach point on the boom.
Install the upper pivot shaft through the cylinder and
boom attach points, inserting the spacers and shims as
noted during disassembly. Shut down the engine.
7. Install end plate, washers, and capscrews which secure
upper pivot shaft to the side of the attachment fitting on
the boom.
8. Evenly tighten the setscrews on the opposite side until
both setscrews make contact with the cylinder, then
loosen both setscrews until a gap of 2 mm (0.08 in) is
attained between end of setscrews and cylinder. Secure
setscrews with nuts.
9. Remove the lifting and supporting devices from the
boom and lift cylinders. Activate the hydraulic system
and check the lift cylinders for proper operation and any
leaks.
6. Boom will not
lower.
a. Low hydraulic oil. a. Check system for leaks. Make repairs
as needed. Fill reservoir.
b. Main relief valve or circuit relief valve
damaged.
b. Repair or replace relief valve.
c. Worn or damaged hydraulic pump
section.
c. Repair or replace pump section.
d. Broken pump shaft. d. Replace pump shaft and seals.
e. Broken pump drive coupling. e. Replace drive coupling.
f. Broken control valve spool. f. Replace control valve.
Symptom Probable Cause Solution
DANGER
Ensure the lifting device is capable of supporting the
boom assembly. Death or serious injury may result if the
lifting device cannot support the load.
Reference Only
To Next Page
Loading...
Need help?
General
