Damper Maintenance - JLG t350 Service And Maintenance Manual

SECTION 3 - CHASSIS & TURNTABLE

Damper Maintenance

The dampers assembled within the overrun coupling is
pressurized. During assembly, the damper is reloaded
and compressed in order that the coupling operates cor-
rectly. Care must be exercised when working on, han-
dling, and disposing of the coupling/damper. This is
especially important if any damage or misuse of the cou-
pling has occurred.
REMOVAL
DO NOT POSITION ANYTHING OR STAND IMMEDIATELY TO THE
FRONT OR REAR OF THE COUPLING ASSEMBLY IN CASE A
DAMPER FAILS DURING THE PROCESS.
1. Pull back the bellows from the coupling to expose
the two retaining bolts.
2. Undo the self locking nut from the rear bolt of the
coupling as shown.
3. Remove the rear bolt; force may be required as the
damper may still be preloaded. Raise the coupling
operating handle in order to fully remove the bolt if
necessary.
4. When the rear bolt is removed the damper will move
forward to rest upon the front bolt.
In some instances a retaining pin is used; located
between the bolt holes. This pin will hold the damper
in its original position and will therefore need to be
removed in the following manner.
a. Undo the self locking nut from the front bolt,
extract the bolt and remove the head.
b. Replace both bolts in the draw tube and finger
tighten the bolts.
3-20
c. Knock out the retaining pin and remove the rear
bolt, this will allow the damper to move forward
and contact the front bolt.
5. From underneath, through the bolt hole in the draw
tube, drill a 3 mm hole into the damper body to a
depth of 8 mm.
OBSERVE NORMAL SAFETY PROCEDURES FOR THE USE OF
HAND TOOLS.
WEAR SAFETY GLASSES.
DO NOT LIE IMMEDIATELY UNDERNEATH THE BOLT HOLE WHEN
DRILLING.
WHEN THE DRILL PENETRATES THE DAMPER BODY GAS WILL
BE ALLOWED TO ESCAPE.
6. The pressure in the damper should now have been
discharged. Remove the self locking nut on the front
bolt of the coupling head. Remove the bolt and the
coupling head. If the bolt is difficult to remove, it indi-
cates that there is still residual force in the damper
and step 5 should be repeated.
7. Remove the rear damper bracket retaining bolts.
Also remove the nuts and spring washer from the
rear of the damper.
8. The de-pressurized damper can now be removed by
sliding the damper forward through the draw tube
and be disposed of.
– JLG Lift – 3121198