JLG 1850SJ Service Manual - Manual (Page 271)

SECTION 5 - BASIC HYDRAULIC INFORMATION & HYDRAULIC SCHEMATICS
3121619 – JLG Lift – 5-101
VALVE PLATE AND ENDCAP
1. Clean valve plate (26) and endcap (34). Install timing pin
(27) in endcap. Verify it is properly oriented with split
facing in or out of slot in valve plate (26) 0.14 ± 0.01
(3.61 ± 0.25 mm) above valve plate surface.
2. Apply a liberal amount of assembly grease to back side
of valve plate surface to hold it in position. Install valve
plate over timing pin, check valve, and bearing cup.
NOTE: To ensure proper pump operation, it is extremely impor-
tant there is no contamination between endcap and valve
plate.
3. Install bearing cone (28) on shaft. Using assembly grease
to hold seal (25), install endcap to housing. Ensure seals
remain properly seated and are not pinched during
assembly. Install and torque four capscrews (33) 94 - 114
ft-lb (127 - 155 Nm), using an alternating pattern. Re-
torque the first screw to ensure proper torque retention.
SHAFT SEAL
1. Lubricate lip of new shaft seal (14) with clean hydraulic
fluid. Place protective sleeve over shaft end to prevent
damage to seal during installation. Install seal with
cupped side toward shaft bearing. Keep seal perpendic-
ular to shaft and press seal in housing just far enough to
clear retaining ring groove. Install retaining ring (15).
Remove installation sleeve.
NOTE: Clean all control parts and apply a light coating of hydrau-
lic fluid before reassembly.
PC CONTROL ASSEMBLY
1. Clean all control parts and apply a light coating of
hydraulic fluid before reassembly.
2. Install spherical end of PC spool (38) in PC bore. Install
new O-ring (39) on PC plug (40.) Install and torque plug
8 - 10 ft-lb (10.8 - 13.5 Nm). Place inner PC spring (52)
and outer PC spring (53) on PC spring guide (51). Install
in PC bore. Place new 0-ring (54) on PC plug (55). Install
so it sits one turn below surface of control housing.
Install set screw (44). Torque to 5.5 - 8.0 ft-lb (7.5 to 10.8
Nm).
11
25
26
28
33
34
29
27
Figure 5-135. Valve Plate and Endcap Installation
14 15
Figure 5-136. Shaft Seal Installation