JLG T350 Service Manual - Manual (Page 55)

SECTION 3 - CHASSIS & TURNTABLE
3121198 – JLG Lift – 3-19
Coupling Head Maintenance
REPLACING
Prior to replacing the coupling head, it is essential to con-
firm the condition of the damper. Test the Damper as out-
lined under DAMPER REACTION TEST.
1. Follow steps 1 thru 4 under Damper Maintenance -
REMOVAL.
2. If you have been able to remove the coupling head/
eye as instructed under Damper Maintenance -
REMOVAL step 4, go to step 5 below, otherwise pro-
ceed with step 3.
3. The damper will now be retained between the front
coupling/eye bolt and the rear damper bracket. It is
now necessary to remove the damper without
destroying it. WARNING: Proceed with caution!
The most efficient method is to remove the rear
damper mounting bracket, but depending upon the
coupling, there may still be tension in the damper.
4. Place a lever against the rear damper in such a man-
ner that once the mounting bracket bolts are
removed the tension can be released slowly. Take
the tension and remove the mounting bracket bolts,
release the tension in the damper.
5. Inspect the shaft for damage, dress burrs, and clean
any dirt as the new coupling will be a close fit on the
shaft.
6. If a new bellows is to be fitted cut the tie-wrap and
discard the old one, fit the new and secure with a tie-
strap.
7. Trial fit the new coupling. It should slide into place
without any undue force. DO NOT hammer the cou-
pling into place, this can damage the coupling itself
or the over-run mechanism. If it proves to be tight,
remove it and thoroughly clean the shaft inspecting
for burrs.
8. Fit the bolts, washers and secure with NEW locking
nuts. DO NOT re-use the old nuts as this is safety
critical. On a T350, torque to 85 ft. lbs. (115 Nm), on
a T500J, torque to 214 ft. lbs. (290 Nm). Fit the plas-
tic nut covers. Where the damper has been removed
ensure that the coupling head rear bolt passes
through the hole in the damper body.
NOTE: If there are any doubts about the condition of the
damper, install a new one.
9. If the damper has been released the rear mounting
bracket will need to be re-fitted. This means that the
damper needs to be compressed so the bolts can
be installed. WARNING: Proceed with caution!
Compress the damper with the lever and secure the
mounting bracket bolts.
10. Reinstall the bellows with the coupling/eye horizon-
tal taking care not to tear or damage the material.
If the replacement coupling/eye is a different part
than the original:
a. Always ensure the corresponding length bolts
are used.
b. Always ensure a compatible bellows is used.
c. Always ensure the hole sizes in the coupling and
draw-bar tube match and the correct size bolts
are used.
DAMPER REACTION TEST
1. Pull the handbrake lever on as far as possible.
2. Push the ball coupling as far back into the overrun-
ning hitch as it will go. This requires force to com-
press and should extend smoothly when released.
3. If the draw tube is impossible to compress, com-
presses with just spring force and no damping resis-
tance, or the extension is very rapid, the damper
must be replaced by carefully following the replace-
ment instructions above.