JLG G12-55A AccuPlace Service Manual - Manual (Page 34)

Boom
3.12 G10-55A & G12-55A AccuPlace
3.4.4 Chain Lubrication
After inspection and before being returned to service,
chains must be lubricated with a quality chain lubricant
(“LUBRIPLATE” Chain & Cable Fluid, “LPS3” or
equivalent).
The lubricant must penetrate the chain joint to prevent
wear. Applying lubricant to the external surfaces will
prevent rust, but the chains should be articulated to
make sure the lubricant penetrates to the working
surfaces between the pins and links.
To prepare the chain for lubrication, the chain plates
should be brushed with a stiff brush or wire brush to
clear the space between the plates so that lubricant can
penetrate to the working surfaces.
Lubricant may be applied with a narrow paint brush or
directly poured on, but the chain should be well flooded
with lubricant and the boom should be extended and
retracted to be sure that the lubricant penetrates to the
working surfaces. All surplus lubricant should be wiped
away from the external surfaces. DO NOT use a solvent
for this wiping operation.
Regular application of lubricant is necessary to make
sure that all working surfaces are adequately lubricated.
In extremely dusty conditions, it may be necessary to
lubricate the chains more often.
Lubrication of chains on vehicles working consistently in
extreme hot or cold conditions requires special
consideration. It is important that a reputable lubrication
specialist, a JLG Distributor or the vehicle distributor be
consulted for guidance.
3.4.5 Retract Chain Removal
The following section explains the removal of the retract
chains without removing the boom assemblies.
Note: The retract chain on the bottom of the boom must
be removed to gain access to the inner retract chain.
To remove the 1 in. retract chain from the third to first
boom sections:
1. Park the machine on level ground. Place the
transmission control lever in (N) NEUTRAL, engage
the parking brake switch, level the boom and shut
the engine OFF.
2. Place a Do Not Operate Tag on both the ignition key
switch and the steering wheel, stating that the
machine should not be operated.
3. Remove the battery negative (-) cable from the
battery negative (-) terminal.
4. Attach a suitable sling to the extend/retract cylinder.
Remove the extend/retract cylinder support.
5. Remove the rod end pin and lower the cylinder onto
the frame rails. Lowering the extend/retract cylinder
will allow access to the chains.
6. Remove tension from the chain by backing off the
jam nut and adjusting nut (1).
7. Remove the four bolts (2) from the chain adjustment
block.
8. Remove the chain from the clevis (3) at the block.
9. Install a nylon tie wrap through the holes of the
removed chain, making a loop with a tie wrap and tie
a rope to the loop.
10. At the rear of the boom, pull the chain to the rear to
allow slack for removal.
11. Remove the chain from the clevis and drop it free
from the boom.
12. Holding a rope at the front adjustment block,
carefully pull the chain out through the back of the
boom.
13. Untie the rope and leave it in place for reinstallation
of the chain.
To remove the 3/4 in. retract chain from the fourth to
second boom sections:
1. Remove the jam nut (4) from the chain clevis
installed in the chain adjustment block.
2. Back off the adjusting nut fully on the chain clevis.
Do not remove the nut from the clevis.
3. Remove the chain from the clevis, install a nylon tie-
wrap through the holes in the chain, making a loop
with the tie-wrap and tie a rope to the loop.
4. Move to the back of the boom and pull the chain to
the rear to allow slack for removal.
5. Remove the chain from the clevis and drop it free
from the boom.
6. Holding the rope at the front, carefully pull the chain
out through the back of the boom until it’s free.
7. Untie the rope and leave it in place for reinstallation
of the chain.
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