Operation and maintenance manual

Section 230-0060
SM 1410 Rev 2 2-02
3
(2 500 lbf/in²).
Should oil at the inlet side of the valve exceed
172 bar (2 500 lbf/in²), pilot poppet (33) will be forced
off its seat. Oil will flow through an internal passage
and exit from port 'A' to the hydraulic oil tank. When
pressure is relieved, tension of spring (32) will force
pilot poppet (33) to re-seat.
REMOVAL
Numbers in parentheses refer to Fig. 1.
WARNING
To prevent personal injury and property
damage, be sure wheel blocks, blocking
materials and lifting equipment are 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. Operate the treadle valve
continuously to relieve pressure in the braking system.
2. Block all road wheels and place the battery master
switch in the 'Off' position.
3. Remove blanking cap from remote drain line at the
bottom of the hydraulic tank. Install a length of hose on
remote drain fitting, open drain cock and drain
hydraulic oil into a suitable container. Close drain
cock, remove hose and reinstall blanking cap.
4. Clean body control valve housing (41) and
surrounding area with a suitable solvent. Identify and
tag all hydraulic and servo control lines connected to
body control valve, to aid in 'Installation'.
5. With suitable containers available to catch spillage,
disconnect hydraulic and servo control lines from
control valve. Drain the oil from the lines into the
container and discard all 'O' rings. Cap hydraulic lines
and control valve ports to prevent ingress of dirt.
6. Support body control valve with a suitable lifting
device and remove mounting hardware securing body
control valve to the cradle assembly. Remove body
control valve to a clean area for disassembly.
Body System - Body Control Valve
DISASSEMBLY
Numbers and letters in parentheses refer to Fig. 1.
WARNING
Spring loaded parts. Use care when removing
end cap, retainers and plugs to prevent sudden
release of spring tension behind these parts.
Personal injury or property damage could
result if care is not taken.
Note: Clean entire control valve assembly with a
suitable solvent and dry thoroughly prior to
disassembly.
Valve Body
1. If required, remove bolts (23), lockwashers (24),
blanking plate (25) and 'O' ring (26) from port 'B' in
valve housing (41). Discard 'O' ring (26).
2. If required, remove bolts (23), lockwashers (24),
cover plate (27) and 'O' ring (28) from port 'F' in valve
housing (41). Discard 'O' ring (28). If required, remove
plug (42) and seal (43) from cover plate (27).
Control Spool
1. Clean the entire body control valve assembly with a
suitable solvent and dry thoroughly. Remove caps
from valve housing (41) ports.
2. If required, clamp body control valve assembly in a
soft jawed vice. Take care to avoid damaging valve
housing (41) machined surfaces.
3. Remove capscrews (14) securing pressure
reducing valve (13) from mounting block (20).
Withdraw pressure reducing valve (13) from mounting
block (20).
4. Remove capscrews (22) securing mounting block
(20) to end cap (10). Remove mounting block (20) and
discard 'O' ring (21).
5. If required, remove plug (19) from mounting block
(20) and discard 'O' ring (18).
6. Repeat steps 3 to 5 for opposite end of valve
housing (41), end cap (17).