Published 08-25-09, Control # 077-04 2-71
RT9130E SERVICE MANUAL HYDRAULIC SYSTEM
UPPER TELESCOPE CYLINDER
Description
The upper boom telescope cylinder (Figure 2-41) has a
190.5 mm (7.5 in) bore and is internally ported (rod ported).
Oil from the telescope control valve is routed to the cylinder
by external lines. Foreign material is prevented from entering
the cylinder during rod retraction by a wiper ring in the head
and o-ring seals prevent internal and external leakage. The
retracted length of the telescope cylinder is 10604.5 mm
(417.5 in) and a extended length of 19640.55 mm (773.25 in)
from the end of the barrel to the end of the port block on the
rod.
The cylinder weighs 921.4 kg (2022 pounds).
Maintenance
Disassembly
NOTE: Replace all cylinder seals and o-rings with new
ones anytime the cylinder is disassembled.
1. Using a chain wrench, unscrew the cylinder head from
the cylinder barrel.
2. Remove the cylinder rod assembly from the cylinder
barrel and cover the barrel to avoid contamination.
NOTE: Align old seals in order of removal to facilitate
installation of new seals.
3. Remove the guide lock ring at the top of the piston to
gain access to the setscrew securing the piston to the
cylinder rod.
4. Remove the set screw and discard.
5. Unscrew the piston from the rod.
6. Remove the remaining guide lock ring and hydrolock
seal assembly from the outside of the piston.
7. Remove the o-ring and backup rings from the inside of
the piston.
8. Remove the spacer from the rod.
9. Remove the cylinder head from the rod.
10. Remove the o-ring and backup ring from the outside of
the cylinder head.
11. Remove the wear ring, buffer seal, deep Z rod seal and
wiper ring from the inside of the head.
Inspection
1. Clean all parts with solvent and dry with compressed air.
Inspect all parts for serviceability.
2. Stone out minor blemishes and polish with fine crocus
cloth.
3. Clean with solvent and dry with compressed air parts
that have been stoned and polished.
4. Inspect the barrel for scoring.
Assembly
1. If removed, install the holding valve. Refer to VALVES in
this section.
NOTE: Lubricate new seals and rings with clean hydraulic
oil. Orient wear ring gaps 180° apart.
2. Install the wiper ring and wear ring on the inside of the
cylinder head.
3. Install the buffer seal assembly and deep Z rod seal
inside the head. Make sure the seals are properly
assembled and installed in the correct direction.
DANGER
Do not use air pressure to remove the cylinder rod. Use
only controlled hydraulic pressure.
CAUTION
Do not damage the cylinder rod chrome surface.
CAUTION
Do not scratch the grooved and gland surfaces.
CAUTION
Clean all surfaces and remove all burrs and nicks.
Replace all damaged or worn parts.
CAUTION
Do not scratch the grooved and gland surfaces or
damage the seals and o-rings.
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