JLG 601S ANSI Service Manual - Manual (Page 90)

SECTION 3 - CHASSIS & TURNTABLE
3-50 – JLG Lift – 3120746
4. Remove the piston (15) from the power plate (21) by
introducing low pressure air into the hydraulic inlet
and make sure the piston is directed away from the
operator. Remove the o-rings (17&19) and backup
rings (16 & 18) from the piston O.D. and I.D.
grooves. Do not remove backup rings (16 & 18)
unless replacement is necessary because they will
be damaged.With shaft protrusion downward,
remove end cover (13) by removing capscrews (12).
Inspection
1. Clean all parts thoroughly.
2. Closely inspect all parts for excessive wear, cracks
and chips. Replace parts as necessary.
3. Discard seals and o-rings.
4. Closely inspect bearings and bearing contact sur-
faces. Replace as necessary.
Assembly
THERE MAY BE MORE PARTS IN A SERVICE KIT THAN YOUR
BRAKE REQUIRES. CHECK THE PARTS LIST CAREFULLY FOR
THE EXACT QUANTITY. IN THE CASE OF SPRINGS, SPACE THE
SPRINGS AS SHOWN IN THE FIGURE.
1. Worn o-rings and damaged or worn Teflon backup
rings must be replaced prior to assembly.
2. The cylinder of the power plate, piston, and o-rings
must be clean prior to assembly and pre-lubed with
the system hydraulic fluid.
THE DEPTH THE PISTON IS INSTALLED INTO THE POWER PLATE
IS CRITICAL. THE SURFACE OF THE PISTON AT THE CUTOUTS
MUST BE FLUSH TO 0.120 IN BELOW THE SURFACE OF THE
POWER PLATE. DO NOT EXCEED THE 0.120 DEPTH OR THE PIS-
TON WILL COCK RESULTING IN A COMPLETE LOSS OF BRAK-
ING.
3. Assemble the piston (15) into the power plate (21)
using a shop press, being careful not to damage the
o-rings or Teflon back-up rings. Visually align the
center of the cutouts in the piston with the torque pin
(3) holes in the power plate (21).
4. For replacement of the seal;
a. Use a shop press to install the bearing (4) into
the housing. Press on the outer surface of the
bearing only. Install the retaining ring (5) into the
groove.
b. Press the seal (6) into the housing (1) until it is
flush with the face of the housing. The lip of the
seal must face towards the bearing.
5. Press the shaft into the housing until it stops on the
bearing. Support the inner race of the bearing dur-
ing the press operation.
6. Rotating discs must be clean and dry. The lining
material and mating surfaces of the stationary discs
must be thoroughly clean and free of debris. Worn
or scored rotating discs must be replaced.
7. Install bolts (24) with washers (23) in the power plate
(21). Tighten sequentially, one turn at time, until the
power plate is properly seated. Torque 105 to 115
foot-pounds.