SECTION 2 - SERVICE PROCEDURES
31215808
2-17
Piston
Visually inspect the outside surface for scratches or polishing.
Deep scratches are unacceptable. Polishing indicates uneven
loading and when this occurs, the diameter should be checked
for out-of-roundness. If out-of-roundness exceeds 0.007 in.,
this is unacceptable. Check the condition of the dynamic seals
and bearings looking particularly for metallic particles embed-
ded in the bearing and in the piston seal surface. Remove the
seals and bearings. Damage to the seal grooves, particularly
on the sealing surfaces, is unacceptable. In the event that an
unacceptable condition occurs, the piston should be replaced.
Tube Assembly
Visually inspect the inside bore for scratches and pits. There
should be no scratches or pits deep enough to catch the fin-
gernail. Scratches that catch the fingernail but are less than 0.5
in. long and primarily in the circumferential direction are
acceptable provided they cannot cut the piston seal. The
roughness of the bore should be between 10 and 20 ì inches
RMS. Significant variation (greater than 8 ì inches difference)
are unacceptable. In the event that an unacceptable condition
occurs, the tube assembly should be repaired or replaced.
RETAINING RING
GROOVE
WEAR
RING
PISTON
SEAL
O-RING
O-RING
BACKUP
RING
CYLINDER
HEAD
RETAINING
RING
ROD
SEAL
ROD
WIPER
CYLINDER
ROD
CYLINDER
HEAD
WHEN ASSEMBLING
CYLINDER
APPLY ANTI-SEIZE
COMPOUND
AROUND THE HEAD
IN THIS AREA ONLY
PISTON
LOCKNUT
TORQUE
175-200 ft.lbs.
(237-271 Nm)
CYLINDER
TUBE
ASSEMBLY
Figure 2-1. Lift Cylinder Internal Component Assembly Cross-Section
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