JLG 450A_AJ Series II Service Manual - Manual (Page 69)

SECTION 3 - CHASSIS & TURNTABLE
3121290 – JLG Lift – 3-29
Assembly
1. Install new O-ring (1) and piston seal (2) to servo piston
(3). Install piston seal over O-ring.
NOTE: Installing piston seal stretches it, making it difficult to
install servo piston in its bore. Allow 30 minutes for seal to
relax after installation. To speed up seal relaxation, com-
press seal by installing piston head in servo cavity in end-
cap and let it stand for at least five minutes.
2. After piston seal has relaxed, lubricate and install servo
piston into housing bore. Align piston with ball socket
facing inside of housing.
COMPRESSED SPRING MAY FLY OUT AND CAUSE SERIOUS INJURY. COMPRESS-
ING BLOCK SPRING REQUIRES ABOUT 80 TO 90 LBF (350 TO 400 N) OF FORCE.
USE A PRESS SUFFICIENT TO MAINTAIN THIS FORCE WITH REASONABLE
EFFORT. ENSURE SPRING IS SECURE BEFORE ATTEMPTING TO INSTALL SPIRAL
RETAINING RING. RELEASE PRESSURE SLOWLY AFTER RETAINING RING IS
INSTALLED.
3. Install inner block spring washer (4), block spring (5),
and outer washer (6) in cylinder block. Using a press,
compress block spring enough to expose retaining ring
groove. Wind spiral retaining ring (7) into cylinder block.
4. Turn block over and install retaining ring (8), hold-down
pins (9), and ball guide (10) to cylinder block.
3
2
1
3
1. O-ring
2. Piston Seal
3. Servo Piston
Figure 3-18. Servo Piston
7
6
5
4
8
9
10
12
11
4. Block Spring Washer
5. Block Spring
6. Outer Washer
7. Spiral Retaining Ring
8. Retaining Ring
9. Holddown Pins
10. Ball Guide
11. Piston
12. Slipper Retainer
Figure 3-19. Cylinder Kit Assembly