Terex RT700 - Hydraulic Cylinders Maintenance

HYDRAULIC CYLINDERS MAINTENANCE
HYDRAULIC CYLINDER DISASSEMBLY
GENERAL
Do not disassemble a cylinder unless no other maintenance
procedure can correct the problem. All overhaul or new cyl-
inder installations should be done in a clean, dust-free atmo-
sphere with all ports plugged until hose connections are
made.
BOOM EXTEND CYLINDERS
The outer case is the “moving” member of the cylinder. The
hollow shaft is “stationary”. The hollow shaft ports the pis-
ton and case end to retract the cylinder while a tube within
the “shaft” ports the piston and head gland to extend the cyl-
inder.
Disassemble the boom extend cylinders by the following
procedure:
1. Using an adjustable spanner wrench, remove head gland
of cylinder. As head gland is loosened, it may be neces-
sary to begin to move rod out of cylinder tube.
2. With head gland fully disengaged, remove as an assem-
bly, piston rod, head gland, and piston assembly.
3. To remove piston, remove the setscrews which secure
the piston retaining ring to piston rod.
Note: There are two types of cylinders used on the machine.
Both cylinders have setscrews located under the wear
ring to retain the piston to the rod.
Note: After removing the piston, the retainer can be
removed to reseal the inner tube.
BOOM LIFT CYLINDER
Disassemble the boom lift cylinder by the following proce-
dure:
1. Remove the locking socket head cap screw from the
draw ring. With an adjustable spanner wrench, remove
the draw ring and head gland.
Failure to remove the locking capscrew may result in
serious thread damage.
Note: One turn off, back 1/3 turn alternately.
2. Remove the head gland, shaft, and piston from the case.
3. Remove piston and gland by removing setscrews in
retaining collar removing retaining nut. Remove piston
and gland from rod. Access to all seal units is now pos-
sible.
HYDRAULIC CYLINDER INSPECTION
Wash the cylinder bore and all the components with solvent
and make the following inspection:
CYLINDER BORE
For signs of scoring and deep scratches. In the event of any
defects, reassemble the entire cylinder and contact your dis-
tributor.
CYLINDER SHAFT
For dents, deep scratches, or damaged chrome plating. File
any sharp edges on ends of shaft to protect the seals upon
reassembly. Always protect the shaft finish when clamping
in a vice or when welding against weld splatter.
PISTON RINGS
For cracks or other damage. Particularly check the interlock-
ing ends that they are not missing or broken.
PISTON SEALS
For signs of severe damage. Do not remove unless replace-
ment is necessary.
SERVICE AND ADJUSTMENTS
Issued: August 20036 - 20RT700 Series