JLG G12-55A AccuPlace Service Manual - Manual (Page 30)

Boom
3.8 G10-55A & G12-55A AccuPlace
21. Install the top front chain roller (7) to the second and
third boom sections.
22. Install the cushion clamps around the hoses on the
first boom section.
23. Connect the top front chain clevises to the chains,
then connect the chains to the first and second
boom sections.
24. Adjust the retract chain (8) at the bottom front of the
first boom section to 2 7/8 in. (73 mm) for the initial
setup.
25. Install the auxiliary hydraulic hoses and electrical
cables to the boomhead of the fourth boom section.
26. Using a suitable sling, install the tilt cylinder to the
front of the boom.
27. Using a suitable sling, install the extend/retract
cylinder and support to the second and first boom
section.
28. Reconnect the latch on the Boom Length Sensor
cable to the third boom section. Refer to Section
9.11.13, “Boom Length Sensor.”
3.3.8 Boom Installation
1. Park the machine on a hard, level surface, place the
transmission control lever in (N) NEUTRAL, engage
the park brake, chock the wheels and shut the
engine OFF.
2. Using suitable slings, balance the boom assembly,
lift and carefully guide the boom into place. Align the
frame pivot bore with the boom assembly pivot bore.
Install the boom pivot pin.
3. With the sling still in place, install the compensation
cylinder, pins and bolts.
4. With the sling still in place, install the rod end of the
left lift/lower cylinder, pin and lock bolt. Repeat for
the right side lift/lower cylinder.
Note: Raising the boom up or down with the sling may
be necessary so the boom, compensation and lift/lower
cylinder bores can be aligned for easier pin installation.
Note: Grease the boom pivot bore, compensation
cylinder rod ends, lift/lower cylinder rod end and pins
before installing.
5. Uncap and reconnect the previously labeled
hydraulic hoses to the extend/retract cylinder.
6. Uncap and connect any remaining hydraulic fittings
to their appropriate locations.
7. Recheck the wear pad gaps to ensure they meet the
minimum gap requirement. Shim if necessary.
8. Ensure that the boom chains are properly adjusted.
Refer to Section 3.5, “Boom Section Separation
Adjustment.”
9. Install and reconnect the boom angle sensors to
both the left and right side of the boom. Refer to
Section 9.11.12, “Boom Angle Sensors.”
10. Connect the battery negative (-) cable to the battery
negative (-) terminal.
11. Start the engine and operate all boom functions
several times. Check for leaks, and check the
hydraulic fluid level in the reservoir; add fluid if
required.
12. Clean up all debris, hydraulic fluid, etc., in, on, near
and around the machine.
13. Close and secure the engine cover.
MAP0740
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