Operation and maintenance manual

Body System - Main Hydraulic Pump
Section 230-0050
SM 1394 Rev1 12-04
2
DISASSEMBLY
Numbers in parentheses refer to Figs. 1.
1. Place pump assembly in a soft-jawed vice, and
clamp on body (1) casing. Match mark port body (1),
front cover (2) and mounting flange (3) to aid in
assembly.
Note: Do not clamp vice on machined surfaces of the
pump at any time.
2. Remove capscrews (16) securing mounting flange
(3) and front cover (2) together.
3. Tap mounting flange (3) with a soft hammer and
remove it from front cover (2).
Note: Do not attempt to pry the pump units apart with
a large screwdriver or pry bar. The machined surfaces
of the mounting flange (3) or front cover (2) may be
damaged.
4. Remove and discard shaft seals (18 & 20).
5. Remove capscrews (15) securing front cover (2)
and body housing (1) together.
6. Tap front cover (2) with a soft hammer and remove
from body housing (1).
Note: Do not attempt to pry the pump units apart with
a large screwdriver or pry bar. The machined surfaces
of the body housing (1) or front cover (2) may be
damaged.
7. Remove and discard ring seal (10) from body
housing (1).
8. Remove wear plate (13), wear plate seal (8) and
backup seal (9) from shaft front cover (2). Note the
position of wear plate seal (8) in wear plate (13)
groove, for proper assembly.
9. Remove driveshaft gear (11) and driven gear (12)
from body housing (1).
10. Remove wear plate (14) and wear plate seal (8)
from body housing (1). Note the position of wear plate
seal (8) in wear plate (14) groove, for proper
assembly.
11. Using a suitable puller, remove bearings (7) from
shaft front cover (2), only if they are being replaced.
As driveshaft and gear (11) rotates, driven gear (12)
rotates in the opposite direction. Pockets between the
drive and driven gear teeth carry oil from inlet port 'A',
around gear housing (2) ID, to outlet port 'B'. As the
gear teeth re-mesh, oil is forced out of outlet port 'B' to
the body control valve. Refer to Section 230-0060,
BODY CONTROL VALVE.
The maximum oil delivery of the hydraulic pump is
fixed by the width of its respective gear set and the
speed at which driveshaft and gear (11) rotates.
Note: Never drive a pump in the wrong direction of
rotation, as pump seizure may result.
REMOVAL
Numbers in parentheses refer to Fig. 1.
WARNING
To prevent personal injury and property
damage, be sure lifting equipment is properly
secured and of adequate capacity to do the job
safely.
1. Position the vehicle in a level work area, apply the
parking brake and switch off the engine. Operate
steering right and left several times to relieve pressure
in the steering system.
2. Block all road wheels and place the battery master
switch in the 'Off' position.
3. Remove hydraulic tank remote drain plug and drain
hydraulic oil into a suitable container. Reinstall drain
plug in hydraulic tank remote drain fitting.
4. Clean pump housing and disconnect inlet line and
outlet line from pump assembly. Drain oil in hydraulic
lines into a suitable container. Cap hydraulic lines and
plug pump ports to prevent ingress of dirt.
5. Support pump assembly with suitable lifting
equipment. Remove bolts (4) and lockwashers (5)
securing pump assembly to the transmission. Remove
pump assembly from the transmission and discard 'O'-
Ring (6).
6. Wash outside of the pump assembly thoroughly,
with a suitable solvent, and move to a clean work area
for disassembly.