JLG 500RTS ANSI Service Manual - Manual (Page 32)

SECTION 2 - PROCEDURES
2-16 – JLG Sizzor – 3120696
9. Disassemble the piston block as follows:
NOTE: The following parts will be needed to disassemble
the piston block:
2 ea. 3/8 I.D. x 1-1/8 O.D. flat washers
1 ea. 3/8 x 3-1/4 N.C. capscrew
1 ea. 3/8 N.C. nut
a. Place one of the flatwashers over the 3/8 x 3-1/4
capscrew and place this through the center of
the piston block.
b. Place the other washer over the capscrew and
let it rest on the three pins.
c. Screw nut on capscrew and compress the
spring inside the piston block.
d. Using a pair of snap ring pliers, remove internal
snap ring.
e. Remove bolt, nut, and two washers.
f. Remove two washers, spring, three pins, and
pin keeper.
10. Remove thrust race, shaft seal, washer, and drive
shaft from housing.
11. Remove two snap rings, thrust washers, and thrust
bearing from drive shaft.
Inspection
1. Wash all parts thoroughly in a suitable solvent.
2. Examine needle bearings in housing and backplate.
If needles are free of excessive play and remain in
bearing cage, there is no need to replace bearing.
3. Inspect thrust washers and thrust bearing. All sur-
faces should be free of any signs of wear or fretting.
4. Inspect spider and pivot. Conical surfaces should be
free of wear and score marks.
5. Inspect pistons. The O.D. surface should be smooth
and free of scoring. Shoes should be snug fit to pis-
ton. Face of shoes should be flat and free of scoring
and flaking. Do not lap piston shoes.
6. Inspect piston block; bores should be free of scor-
ing. Surface that contacts backplate should be
smooth and free of grooves or metal build-up. Do
not lap piston block.
7. Inspect thrust race; surface should show no signs of
scoring or grooves.
8. Inspect flat surface on backplate; it should be free of
excessive scoring or metal build-up. Do not lap
backplate.
9. Inspect drive shaft for fretting in bearing areas.
Check spline area for twisted or broken teeth. If
keyed shaft, check for cracked or chipped keyway.
Assembly
NOTE: Use filtered system oil to lubricate all critical moving
parts before assembly.
1. Install one snap ring in rear groove of drive shaft.
Install one thrust washer, thrust bearing, and second
thrust washer on drive shaft. Install second snap ring
in front groove on drive shaft.
2. Replace needle bearing in housing if necessary.
Install shaft in housing assembly and install washer.
Oil I.D. of new shaft seal and press into position.
Retain with snap ring.
3. Compress pin keeper and install in spline area of
piston block.
4. Install three pins in special grooves of spline with
head end of pin toward inside of block.
5. Install one washer, spring, and second washer. Use
two 3/8 I.D. washers, 3/8 N.C. nut and 3/8 x 3-1/4
capscrew to compress spring and retain with snap
ring. Remove 3/8 N.C. nut, 3/8 x 3-1/4 capscrew and
two washers.
6. Install pivot, spider, and piston assemblies in piston
block assembly.
7. Lubricate thrust race and install in housing assem-
bly.
8. Install piston block assembly in housing assembly.
Piston shoes must contact thrust race. Be sure all
parts are in their proper position.
9. Install new needle bearing in backplate if necessary.
10. Install new o-ring on backplate.
11. Install backplate on housing.
12. Install six capscrews and torque to 15 - 18 ft lbs (20 -
24 Nm).
2.21 DRIVE TORQUE HUB - 2WD/4WD REAR
NOTICE
TORQUE HUB UNITS SHOULD ALWAYS BE ROLL AND LEAK
TESTED BEFORE DISASSEMBLY AND AFTER ASSEMBLY TO
MAKE SURE THAT THE UNITS GEARS AND SEALANTS ARE
WORKING PROPERLY.
NOTICE
WHEN REBUILDING A UNIT, USE NEW SEALS AND O-RINGS.
NEVER RE-USE SEALS AND O-RINGS, AS THIS WOULD CAUSE
UNIT TO LEAK.