Inspection - JLG 1850SJ Service And Maintenance Manual

SECTION 5 - BASIC HYDRAULIC INFORMATION & HYDRAULIC SCHEMATICS
NOTE: The pistons are not selectively fitted, however units with
high hourly usage may develop wear patterns. Number the
pistons and bores for reassembly if they are to be reused.
25. Remove the ball guide (K047).
26. Remove the 3 pins (K046).
NOTE: Most repairs do not require block spring removal. Perform
this procedure only if you suspect problems with the block
spring.
27. Turn the block over. Using a press, apply pressure on the
block spring washer (K044) to compress the block spring
(K043). Compress the spring enough to safely remove
the spiral retaining ring (K045). While maintaining pres-
sure, unwind the spiral retaining ring. Carefully release
the pressure and remove the outer block spring washer,
block spring, and inner block spring washer (K042) from
the cylinder block.
RISK OF PERSONAL INJURY: COMPRESSING THE BLOCK
SPRING REQUIRES ABOUT 350 TO 400 N [80 TO 90.LBF ].
USE A PRESS SUFFICIENT TO MAINTAIN THIS FORCE WITH
REASONABLE EFFORT. ENSURE THE SPRING IS SECURE
BEFORE ATTEMPTING TO REMOVE. THE SPIRAL RETAINING
R I N G. R EL E A S E T H E P RE S S U RE S L O W L Y A F T E R T H E
RETAINING.RING IS REMOVED.

Inspection

After disassembly, wash all parts (including the end-cap and
housing) thoroughly with clean solvent and allow to air dry.
Blow out oil passages in the housing and endcap with com-
5-152
K050
K049
K047
K046
P010
K041
K042
K043
K044
K045
pressed air. Conduct inspection in a clean area and keep all
parts free from contamination. Clean and dry parts again after
any rework or resurfacing.
PISTONS AND SLIPPERS
Inspect the pistons for damage and discoloration. Discolored
pistons may indicate excessive heat; do not reuse.
Inspect the running surface of the slippers. Replace any piston
assemblies with scored or excessively rounded slipper edges.
Measure the slipper foot thickness. Replace any piston assem-
blies with excessively worn slippers. Check the slipper axial
end-play. Replace any piston assemblies with excessive end-
play.
Minimum
slipper foot
thickness
Minimum slipper foot thickness and maximum axial end-play
are given in the table below.
J Frame
Slipperfoot thickness
Piston/slipper end play
BALL GUIDE, SLIPPER RETAINER, AND HOLD-DOWN
PINS
The ball guide should be free of nicks and scratches, and
should not be excessively scored. Examine for discoloration
that may indicate excessive heat or lack of lubrication. The slip-
per retainer should be flat, and slippers should fit in the
retainer with minimal side play. Place the hold-down pins on a
flat surface and roll them to make sure they are straight. Dis-
card and replace any damaged parts.
Maximum end play
Slipper
K050
3.23 mm
[0.127 in]
0.05 mm
[0.002 in]
Slipper
retainer
Ball guide
Hold down pins
3121619