Manitowoc Grove RT770E, Руководство по техническому обслуживанию

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2-75
GROVE
RT770E HYDRAULIC SYSTEM
2
Published 11/26/2014, Control # 447-05
OUTRIGGER EXTENSION CYLINDER
Description
The extension cylinder Figure 2-39 has a 63.5 mm (2.5 in)
diameter bore.
Each cylinder has a retracted length of 231.4 cm ±30.4
(91.12 in ±12) from the center of the rod bushing to the
center of the barrel bushing. The stroke of each cylinder is
196.9 cm (77.50 in) which gives an extended length of
428.2 cm (168.6 in).
A wiper ring prevents foreign material from entering each
cylinder. O-rings and other seals prevent internal and
external leakage.
The cylinder weighs approximately 42.0 kg (92.5 lb).
Maintenance
Disassembly
NOTE: Any maintenance requiring disassembly of the
cylinders should include replacement of all seals
and rings. A seal kit will supply the required items.
1. Drain the oil from the cylinder.
2. Open both ports on the side of the barrel.
3. Secure cylinder barrel in a chain vise without putting
pressure on the side feeder tube preferably in the
vertical position with the rod assembly up.
4. Clean away all dirt from the head. Place protective
padding around the rod near the head to prevent
damaging the chrome. Using a spanner wrench,
unscrew the head from the barrel.
5. Turn the head counterclockwise with a fitted spanner
wrench until the threads disengage.
NOTE: Residual oil will spill over the end of the barrel.
Make Provisions to contain the oil.
6. Using a hoist, extend the rod assembly slowly until the
piston is free of the barrel.
7. Place the rod assembly horizontally on a workbench
taking care not to damage the surface of the rod. Cover
the open end of the barrel to avoid contamination.
8. Remove the locknut from the rod.
9. Remove the O-ring from the rod.
10. The head, piston and spacer can be pulled off the rod
assembly by hand.
NOTE: Arranging discarded seals and rings in the order of
disassembly will aid in installation of new seals and
rings. Pay attention to how each seal and ring is
installed to avoid installing replacement seals and
rings improperly.
11. Remove the wear rings and piston seal from the outside
of the piston.
12. Remove the O-ring and backup ring from the outside of
the head. Remove the rod seal, wear ring and wiper ring
from the inside of the head.
Inspection
1. Inspect the rod. There should be no scratches or pits
deep enough to catch the fingernail. Pits that go to the
base metal are unacceptable. Chrome should be
present over the entire surface of the rod. If lack of
chrome on rod, the rod should be replaced.
2. Inspect rod for straightness. Determine if it can be
straightened or must be replaced.
3. Inspect the head. Visually inspect the inside bore for
scratching or polishing. Deep scratches are
unacceptable. Polishing indicates uneven loading, and
the bore should be checked for out-of-roundness.
4. Inspect the piston. Visually inspect the outside surface
for scratches or polishing, Deep scratches are
unacceptable. Polishing indicates uneven loading, and
the diameter should be checked for out-of roundness.
5. Inspect the barrel carefully for scoring. If barrel is
scored, it must be repaired or replaced.
6. Thoroughly rinse parts, allow to drain, and wipe with a
lint-free rag. Inspect all parts for serviceability.
DANGER
Do not use air pressure to remove the rod. Use only a
source of controlled hydraulic oil pressure if the rod is
hard to move. Injury may result from the cylinder rod
unexpectedly exiting the cylinder barrel.
CAUTION
Exercise extreme care when handling or setting down the
rod. Damage to the rod surface may cause unnecessary
maintenance and expense.
CAUTION
When removing seals and rings, avoid scratching the
grooved and gland surfaces.
CAUTION
Before installing new seals and rings, clean all surfaces
and carefully remove burrs and nicks. Parts displaying
excessive wear or damage should be replaced.