JLG 1850SJ Service Manual - Manual (Page 196)

SECTION 5 - BASIC HYDRAULIC INFORMATION & HYDRAULIC SCHEMATICS
5-26 – JLG Lift – 3121619
CLEANING AND INSPECTION
1. Clean parts thoroughly with approved cleaning solvent.
2. Inspect cylinder rod for scoring, tapering, ovality, or
other damage. If necessary, dress rod with Scotch Brite
or equivalent. Replace rod if necessary.
3. Inspect threaded portion of rod for excessive damage.
Dress threads as necessary.
4. Inspect inner surface of cylinder barrel tube for scoring
or other damage. Check inside diameter for tapering or
ovality. Replace if necessary.
5. Inspect threaded portion of barrel for damage. Dress
threads as necessary.
6. Inspect piston surface for damage, scoring, or distortion.
Dress piston surface or replace piston as necessary.
7. Inspect threaded portion of piston for damage. Dress
threads as necessary.
8. Inspect seal and O-ring grooves in piston for burrs and
sharp edges. Dress surfaces as necessary.
9. Inspect cylinder head inside diameter for scoring or
other damage, and for ovality and tapering. Replace as
necessary.
10. Inspect threaded portion of head for damage. Dress
threads as necessary.
11. Inspect seal and O-ring grooves in head for burrs and
sharp edges. Dress applicable surfaces as necessary.
12. Inspect cylinder head outside diameter for scoring,
damage, ovality, and tapering. Replace as necessary.
13. Inspect cylinder length sensor components for damage.
Replace as needed.
14. Inspect rod and barrel bearings for signs of excessive
wear or damage. Replace as necessary.
a. Thoroughly clean hole, (steel bushing) of burrs, dirt
etc. to facilitate bearing installation.
b. Inspect steel bushing for wear or other damage. If
steel bushing is worn or damaged, rod/barrel must
be replaced.
c. Lubricate inside of steel bushing with WD40 before
installing bushings.
NOTE: Lubrication is not required with nickel plated pins and
bearings. Install pin in composite bushing dry.
d. Press bushing into barrel or rod bushing with cor-
rect size arbor.
15. Inspect port block fittings and holding valve. Replace as
necessary.
16. Inspect oil ports for blockage or presence of dirt or other
foreign material. Repair as necessary.
ASSEMBLY
NOTE: Use proper cylinder seal kit for cylinder assembly. See your
JLG Parts Manual.
Apply a light film of hydraulic oil to all components before
assembly.
IMPROPER SEAL INSTALLATION CAN CAUSE CYLINDER LEAKS AND IMPROPER
CYLINDER OPERATION.
1. Install O-ring (23), O-ring (22), and backup ring (21) in
outside diameter grooves of cylinder head (24).
2. Install two wear rings (25) seal (26), and rod wiper (27), in
cylinder head as shown.
Arbor
Barrel or
Rod Bushing
Composite
Bushing
Composite
Bushing
Figure 5-42. Composite Bushing Installation
21
22
23
24
25
26
27
Figure 5-43. Cylinder Head Seal Kit Installation