JLG 1850SJ Service Manual - Manual (Page 218)

SECTION 5 - BASIC HYDRAULIC INFORMATION & HYDRAULIC SCHEMATICS
5-48 – JLG Lift – 3121619
Jib Telescope Cylinder
Refer to Figure 5-87.
DISASSEMBLY
CCONTAMINATION 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 fitting.
DO NOT FULLY EXTEND CYLINDER TO THE END OF STROKE.
RETRACT CYLINDER SLIGHTLY TO AVOID TRAPPING PRES-
SURE.
2. Operate hydraulic power source and extend cylinder.
Shut down and disconnect power source.
3. Place cylinder barrel in a suitable holding fixture. Clean
outside of cylinder to prevent contamination.
4. Remove two bolts (3), four washers (4), two nuts (9) and
wear pad (5) from bracket (7). Repeat for remaining wear
pad.
5. Remove eight socket head screws (6) and two pad sup-
ports (7) from cylinder head (12). Reinstall one socket
head screw finger-tight.
6. Remove three cartridge valves from valve block.
7. Tap around outside of cylinder head retainer with a suit-
able hammer to break thread-locking compound.
PULLING ROD OFF-CENTER CAN DAMAGE PISTON AND C YLINDER BARREL
SURFACES. USE EXTREME CARE WHEN REMOVING CYLINDER ROD, HEAD, AND
PISTON.
8. Clamp barrel securely. Pull rod assembly out until piston
bottoms to cylinder head.
9. Remove capscrew and pull rod assembly and cylinder
head from barrel.
10. Protect cylinder rod from damage and clamp in a vise or
holding fixture as close to piston as possible.
11. Remove piston assembly (19) from rod (22) with spanner
wrench.
12. Remove spacer assembly (16) from rod (22).
13. Remove cylinder head assembly (12) from rod (22).
3
4
5
6
7
8
9
22
7
12
2
Figure 5-85. Cylinder Head and Wear Pads
SUPPORT TABLE
ROD SUPPORT
Figure 5-86. Cylinder Rod Support