JLG 600SC_660SJC Service Manual - Manual (Page 149)

SECTION 5 - HYDRAULICS
3121607 – JLG Lift – 5-5
5.4 CYLINDER REMOVAL AND INSTALLATION
Main Boom Telescope Cylinder Removal
1. Place machine on a flat and level surface, with main
boom in the horizontal position.
2. Shut down engine. Support main boom basket end with
a prop. (See Figure 5-1., Boom Positioning and Support,
Cylinder Repair).
CAP HYDRAULIC LINES AND PORTS IMMEDIATELY AFTER DISCONNECTING
LINES TO PREVENT ENTRY OF CONTAMINANTS INTO THE SYSTEM.
3. Tag and disconnect hydraulic lines to telescope cylinder.
Use a suitable container to retain residual hydraulic fluid.
Cap hydraulic lines and ports.
4. Remove hardware securing cover plate on bottom of
base boom section and remove cover.
DO NOT ALLOW CABLE TO ROTATE. THIS MAY DAMAGE THE CABLE.
5. Clamp both threaded ends of cable to prevent rotation.
Note: Do not clamp on threads. Remove jam nuts and
loosen adjustment nuts so there is slack in the cables.
(See Section 4 - Boom & Platform).
6. Remove hardware securing push bar to turntable and
telescope cylinder.
7. Using a suitable brass drift, carefully drive push bar pins
from telescope cylinder rod and turntable.
8. Remove hardware securing cable adjustment block to
aft end of the base boom section and remove block.
9. Remove hardware securing telescope cylinder to aft end
of mid boom section.
WHEN REMOVING TELESCOPE CYLINDER FROM BOOM, IT MAY BE NECESSARY
AT SOME POINT TO TURN CYLINDER SLIGHTLY IN ORDER TO CLEAR ASSEM-
BLIES MOUNTED IN THE BOOM. MOVE CYLINDER SLOWLY INTO POSITION OR
DAMAGE TO COMPONENTS MAY RESULT FROM FORCIBLE IMPACT WITH THESE
ASSEMBLIES.
10. Remove bolts securing cable attach bar to top of fly
boom section.
11. Pull telescope cylinder and cables partially from aft end
of base boom section. Secure cylinder with a suitable
sling and lifting device at center of gravity.
12. Carefully remove telescope cylinder and sheave assem-
bly. Place telescope cylinder on a suitable trestle.
Main Boom Telescope Cylinder Installation
1. Route extend cables around extend sheave and secure
cables to the telescope cylinder.
2. Install extend cables mounting blocks to threaded ends
of cables. Loosely install nuts and jam nuts on threaded
end of cables.
DO NOT TO TWIST OR CROSS CABLES DURING INSTALLATION.
3. Secure sling and lifting device at telescope cylinder’s
center of gravity. Lift cylinder to aft end of boom assem-
bly.
4. Install extend cable mounting blocks to threaded ends
of cables. Loosely install nuts and jam nuts on threaded
ends of cables.
WHEN INSERTING TELESCOPE CYLINDER INTO BOOM, IT MAY BE NECESSARY
TO TURN C YLINDER SLIGHTLY TO CLEAR ASSEMBLIES MOUNTED IN THE
BOOM. MOVE C YLINDER SLOWLY INTO POSITION OR DAMAGE TO COMPO-
NENTS MAY RESULT FROM FORCIBLE IMPACT WITH THESE ASSEMBLIES.
5. Carefully install telescope cylinder barrel end support
into slots in mid boom and secure with blocks and bolts.
Use Loctite #242 on bolts.
6. Align holes in aft end of fly boom section with holes in
cable mounting block. Secure with mounting hardware.
7. Align holes in aft end of base boom section with holes in
cable mounting block. Secure with mounting hardware.
8. Remove cylinder port plugs and hydraulic line caps. Cor-
rectly attach lines to cylinder ports.
9. Align holes in rod end of telescope cylinder with holes in
push bar. Install push bar pin and secure with mounting
hardware.
10. Align holes in push bar with holes in turntable. Install
push bar pin and secure with mounting hardware.
NOTE: Boom cables must be torqued after telescope cylin-
der installation. (See Section 4.1, Boom Rope Torqu-
ing Procedures)