Boom Telescope Cylinder - JLG 1850SJ Service And Maintenance Manual

SECTION 5 - BASIC HYDRAULIC INFORMATION & HYDRAULIC SCHEMATICS

Boom Telescope Cylinder

Refer to Figure 5-112.
DISASSEMBLY
CONTAMINATION MAY DAMAGE EQUIPMENT. DISASSEMBLE CYLINDER ON A
CLEAN WORK SURFACE IN A DIRT FREE WORK AREA.
1. Connect a suitable auxiliary hydraulic power source to
cylinder port block fitting.
DO NOT FULLY EXTEND CYLINDER TO END OF STROKE. RETRACT CYLINDER
SLIGHTLY TO AVOID TRAPPING PRESSURE.
2. Operate hydraulic power source and extend cylinder.
Shut down and disconnect power source. Adequately
support cylinder rod.
3. Place cylinder barrel in a suitable holding fixture.
ROD SUPPORT
PROTECTED ROD CLAMP
SUPPORT TABLE
Figure 5-109. Cylinder Barrel Support
4. Remove check valves (3), counterbalance valves (4), and
fittings from valve block (2). Discard O-rings. Remove
four capscrews (1) and valve block from rod (7). Discard
O-rings (5, 6).
5. Mark cylinder head (23) and barrel (28) with center
punch marks for later realignment. Remove two cap-
screws (27) and bracket (26).
6. Remove six remaining capscrews (25) and washers (24).
5-100
BARREL CLAMP
7. Tap around outside of Cylinder Head with a suitable
hammer to break thread-locking compound. Unscrew
Cylinder Head (23).
Figure 5-110. Port Block And Rod Removal
PULLING ROD OFF-CENTER CAN DAMAGE PISTON AND CYLINDER BARREL
SURFACES. USE EXTREME CARE WHEN REMOVING CYLINDER ROD, HEAD, AND
PISTON.
8. Clamp barrel securely. Pull rod assembly and cylinder
head from barrel.
9. Protect cylinder rod from damage and clamp in a vise or
holding fixture as close to piston as possible.
ROD SUPPORT
Figure 5-111. Cylinder Rod Support
27
26
23
25
24
28
SUPPORT TABLE
3121619