JLG G12-55A AccuPlace Service Manual - Manual (Page 27)

3.5 G10-55A & G12-55A AccuPlace
Boom
9. Loosen and remove all the wear pads from the front
of the second boom section. Tag each pad, backing
plate, shim and bolts from each location.
10. Place a sling around the third boom section, lift and
slowly pull the third and fourth boom sections (7)
approximately half way out of the second boom
section. Lower the third and fourth boom sections
onto a suitable support.
11. Relocate the sling or using two slings for better
stability, balance the two boom sections and slowly
pull them out of the second boom section being
careful not to damage any surrounding components.
12. Remove the chain (8) from the second boom section
to the third boom section after the boom sections are
free from each other.
13. Lower the third and fourth boom sections onto a
suitable support.
3.3.4 Fourth Boom Section Removal
1. Remove the bottom rear and side bearing pads from
the fourth boom section. Tag each pad, backing
plate, shim and bolts from each location.
2. Loosen and remove the 3/4 in. chain (9) through the
rear of the fourth boom section.
3. Loosen and remove the retract chain roller (10) at
the rear of the third boom section.
4. Loosen and remove the front wear pads and
supports from the third boom section. Tag each pad,
backing plate, shim and bolts from each location.
5. Carefully pull the fourth boom section out of the third
boom section, taking care to protect the chains.
6. Disconnect the chains when the boom sections are
free from each other.
7. Place the fourth boom section onto suitable
supports.
If the hydraulic sub-assembly (11) is going to be
removed:
8. Remove the guide bracket from the front of the
hydraulic sub-assembly.
9. Remove the hardware securing the hydraulic sub-
assembly to the front of the boom.
10. Install a sling on the hydraulic sub-assembly at the
rear of the boom. Slowly pull it loose from the bottom
bracket located on the bottom plate of the fourth
boom section.
11. When the sub-assembly is approximately 25% free
of the boom, fasten the two hose carriers together
(using nylon tie-wraps or nylon straps) to prevent
them from separating.
Note: Do not wrap the hose carrier since it will not
prevent the two hydraulic carriers from moving apart
sideways.
12. Continue to withdraw the sub-assembly, fastening
the hydraulic carriers together as they are removed.
13. When the hydraulic carrier is approximately 75% tied
together, pull the assembly free of the boom.
3.3.5 Fourth Boom Section Installation
1. Clean and lubricate the inside of the boom sections
where the hydraulic sub-assembly rides
(if removed).
2. Using a sling, lift the balanced hydraulic sub-
assembly and slowly insert it into the fourth boom
section.
3. As the first tie wrap nears the boom, remove the tie
wrap and continue inserting the sub-assembly and
removing each tie wrap until the sub-assembly is
fully inserted.
MY1690
7
8
MX0380
9
10
MX0390
11