JLG 450A_AJ Series II Service Manual - Manual (Page 67)

SECTION 3 - CHASSIS & TURNTABLE
3121290 – JLG Lift – 3-27
Inspection
Wash all parts after disassembly (including end-cap and hous-
ing) thoroughly with clean solvent and allow to air dry. Blow
out oil passages in housing and endcap with compressed air.
Conduct inspection in a clean area and keep all parts free from
contamination. Clean and dry parts again after any rework or
resurfacing.
PISTON
Inspect pistons for damage and discoloration. Discolored pis-
tons may indicate excessive heat. Do not reuse.
SLIPPERS
Inspect running surface of slippers. Replace piston assemblies
with scored or excessively rounded slipper edges. Measure
slipper foot thickness. Replace piston assemblies with exces-
sively worn slippers. Check slipper axial end-play. Replace pis-
ton assemblies with excessive end-play.
Minimum slipper foot thickness and maximum axial end-play
are shown in table 3.6.
BALL GUIDE AND SLIPPER RETAINER
Inspect ball guide and slipper retainer for damage, discolor-
ation, or excessive wear. A discolored ball guide or slipper
retainer indicates excessive heat. Do not reuse.
CYLINDER BLOCK
Measure cylinder block height. Replace blocks worn beyond
minimum height specification. Inspect running surface of cyl-
inder block. Replace or resurface worn or scratched blocks.
Blocks may be resurfaced if resurfacing will not reduce block
height below minimum specification shown in Table 3-9, Cyl-
inder Block Measurements.
Table 3-8. Slipper Foot Thickness & End Play
Measurement L Frame K Frame
Slipper Foot Thickness mm
(in.) 2.71
(0.11)
4.07
(0.16)
Piston/Slipper End Play 0.15
(0.006)
Slipper retainer
Ball guide
A
Table 3-9. Cylinder Block Measurements
Measurement L25 L30 L35 K38 K45
Minimum Cylinder Block Height (A) 50.8 (2.00) 50.8 (2.00) 50.8 (2.00) 54.4 (2.14) 54.4 (2.14)
Cylinder Block Surface Flatness 0.002
(0.0000079)
0.002
(0.0000079)
0.002
(0.0000079)
0.002
(0.0000079)
0.002
(0.0000079)