JLG 601S ANSI Service Manual - Manual (Page 52)

SECTION 3 - CHASSIS & TURNTABLE
3-12 – JLG Lift – 3120746
3.3 DRIVE BRAKE - AUSCO
Disassembly
1. With the shaft protrusion downward, disassemble
the parts in the following order; bolts (24) alternately,
washers (23), power plate (21), and gasket.
2. Remove the following parts; stationary discs (14),
rotating discs (12), primary disc (11), torque pins (3),
springs (8&9), and the spring retainer (7).
NOTE: If the bearing and seal are removed for any reason
both must be replaced.
3. Further disassembly is not recommended and
should not be attempted unless necessary to
replace the bearing (4), the seal (6), or the shaft (10).
If further disassembly is needed, proceed as follows;
a. The shaft (10) may be removed by pressing on
the end of the shaft with a shop press.
b. Using an appropriate tool, pry the seal (6) out
from the inside of the brake. Take care not to
damage the bore. Remove the retaining ring (5).
Tap the bearing (4) out with a plastic mallet.
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 3.048 MM (0.120 IN) BELOW THE SURFACE
OF THE POWER PLATE. DO NOT EXCEED THE 3.048 MM (0.120
IN) DEPTH OR THE PISTON WILL COCK RESULTING IN A COM-
PLETE LOSS OF BRAKING.
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.