JLG 680S, Service And Maintenance Manual

Page: 118 / 530

SECTION 3 - CHASSIS & TURNTABLE
3-66 3121234
CYLINDER BLOCK
Measure the cylinder block height. Replace blocks worn
beyond the minimum height specification. Inspect the run-
ning surface of the cylinder block. Replace or resurface worn
or scratched blocks. Blocks may be resurfaced to the specifica-
tions shown in the drawing, provided resurfacing will not
reduce the block height below the minimum specification.
Table 3-4, Cylinder Block Measurements.
BALL GUIDE AND SLIPPER RETAINER
Inspect the ball guide and slipper retainer for damage, discol-
oration, or excessive wear. A discolored ball guide or slipper
retainer indicates excessive heat. Do not reuse.
VALVE PLATE
The condition of the valve plate is critical to the efficiency of
the motor. Inspect the valve plate surfaces carefully for exces-
sive wear, grooves, or scratches. Replace or resurface grooved
or scratched valve plates. Measure the valve plate thickness
and replace if worn beyond the minimum specification. Valve
plates may be resurfaced to the specifications shown in the
drawing, provided resurfacing will not reduce the thickness
below the minimum specification.
SWASHPLATE AND JOURNAL BEARINGS
Inspect the running face, servo ball-joint and swashplate jour-
nal surfaces for damage or excessive wear. Some material
transfer may appear on these surfaces and is acceptable pro-
viding the surface condition meets specifications shown. Mea-
sure the swashplate thickness from the journals to the running
face. Replace swashplate if damaged or worn beyond mini-
mum specification. Replace swashplate if the difference in
thickness from one side to the other exceeds specification.
Inspect the journal bearings for damage or excessive wear.
Replace journal bearings if scratched, warped, or excessively
worn. The polymer wear layer must be smooth and intact.
A
Table 3-4. Cylinder Block Measurements
Measurement L25 mm (in.) L30 mm (in.) L35 mm (in.) K38 mm (in.) K45 mm (in.)
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
(7.9)
0.002
(0.0000079)
0.002
(0.0000079)
0.002
(0.0000079)
0.002
(0.0000079)
Slipper retainer
Ball guide
3.83 mm [0.151 in] min.
0.025 mm
[0.001 in]
0.0076 mm
[0.00030 in]
convex max
LV
25.8 mm
[1.015 in]
24.6 mm
[0.969 in]
KV
Thickness equality
side to side:
0.05 mm [0.002 in]
0.0025 mm
[0.0001 in]