Manitowoc Grove RT770E, Руководство по техническому обслуживанию

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HYDRAULIC SYSTEM RT770E
2-78 Published 11/26/2014, Control # 447-05
OUTRIGGER JACK CYLINDER
Description
The outrigger jack cylinder Figure 2-40 has a 11.4 cm (4.5 in)
diameter bore. A port block is welded to the rod of each
cylinder and a pilot operated check valve is threaded into
each port block.
The retracted length of the cylinder from the end of the barrel
to the center of the rod’s port block rod bushing is 122.0 cm
±0.30 (48.12 in ± 0.12). The stroke of the cylinder is 63.5 cm
(25.0 in) which gives an extended length of 185.8 cm
(73.12 in).
A wiper ring prevents foreign material from entering the
cylinder. O-rings and other seals prevent internal and
external leakage.
The cylinder weighs approximately 63.30 kg (139.5 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. Open ports and drain the oil from the cylinder.
2. Secure cylinder barrel in a chain vise preferably in the
vertical position with the rod assembly up at about chest
level.
3. With the ports open, extend rod assembly with a hoist
enough to access the top of the head with a spanner
wrench.
NOTE: Do not extend the rod completely. Oil or oil/air
mixture may rapidly exit out of the ports during
extension. Shield the work area from the exiting oil.
4. Turn the head counterclockwise with a fitted spanner
wrench until the threads disengage.
5. Extend the rod assembly slowly until the piston is free of
the barrel.
6. Place the rod assembly horizontally on a workbench
taking care not to damage the surface of the rod. Cover
the barrel opening to avoid contamination.
7. Remove the piston seal to gain access to the setscrew.
Using a 3/16 inch allen wrench, remove the setscrew
from the piston.
8. Turn the piston counterclockwise and remove with a
fitted spanner wrench.
9. Remove the spacer and head from the rod.
10. Remove the seals from the outside of the piston and the
back up rings and O-ring from the inside of the piston.
11. Remove the O-ring and backup ring from the outside of
the head and the wear rings, buffer seal, rod seal 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.
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.