Terex TS14G, Maintenance Manual

Page: 190 / 376

Steering System - Steering Valve
Section 220-0090
SM 1765 2-99
4
REMOVAL
Numbers in parentheses refer to Fig. 1.
WARNINGS
Hydraulic fluid pressure will remain within the
system after engine shutdown. To prevent
personal injury and property damage, turn
steering wheel several times in each direction
to relieve pressure in the system.
To prevent personal injury and property
damage, be sure wheel blocks are properly
secured and of adequate capacity to do the job
safely.
1. Position the vehicle in a level work area, ensure
bowl and apron are fully lowered. Apply the parking
brake and switch off the engine. Operate the steering
in both directions several times to relieve any pressure
in the steering system.
2. Place the battery master switch in the 'Off' position
and block all road wheels.
3. Thoroughly clean the exterior of the steering valve
and its surrounding area to prevent dirt from entering
the valve ports or hydraulic lines during removal.
Note:
If steering valve is being serviced to correct a
suspected spool seal leak, the condition of nut (20)
and washer (22) should be inspected before removing
the steering valve. Replace nut (20) and washer (22),
if defective. Nut (20) should be torque tightened to
50 Nm (35 lbf ft), lubricated. If valve continues to leak,
further servicing is indicated.
4. Identify and tag all hydraulic oil lines, to aid in
installation. With a suitable container available to catch
spillage, disconnect hydraulic lines from steering
valve. Cap all lines and plug all ports of the steering
valve to prevent ingress of dirt.
5. Disconnect the link bar and rod end from steering
valve spool (47).
6. Remove mounting hardware from steering valve
and transfer steering valve to a clean area for
disassembly.
DISASSEMBLY
Numbers in parentheses refer to Fig. 1 & 2.
1. If required, remove fittings from steering valve and
identify to aid in assembly.
2. Remove seat (1) and ‘O’ rings (2 & 3) from valve
body (6). Shake out cross-over relief valve (4)
assembly and spring (5) being careful not to damage
valve. Discard ‘O’ rings (2 & 3). Repeat process for
other cross-over relief valve (4) assembly.
Note:
Do not disassemble cross-over relief valve (4)
assemblies. Valves are pressure set at 145 bar
(2 100 lbf/in²) at assembly. If cross-over relief valve (4)
is defective it must be replaced with a new assembly.
3. Remove cap (19) and ‘O’ ring (11) from valve body
(6). Discard ‘O’ ring (11).
WARNINGS
Use a soft drift and drive when removing lock
plunger to prevent property damage to lock
plunger and personal injury due to flying
chips.
4. Remove plunger cap (10) and ‘O’ ring (11) from
opposite side of valve body (6). Discard ‘O’ ring (11).
Tap lock plunger (18) assembly out cap (10) side,
using a soft drift and drive.
5. Remove cap screws (53) and lockwashers (16) and
lift off cover (9). Remove and discard breather plug
(52) from the cover.
6. Hold the link bar end of the control spool (47)
securely across the flats and loosen nut (38) on the
opposite end. Back the nut off slowly to release the
compression of spring (42). Remove nut (38), washer
(39), first washer (40), spacer (41), spring (42) and
second washer (40). Lift off shims (37 & 44) and plate
(43). Discard the shims (37 & 44) if they are damaged.
Remove washer (45) and seal (46) from valve body (6)
bore. Discard seal (46).
7. Remove bolts (51) and lockwashers (50). Remove
plate (49) and wiper (48). Discard wiper (48), if
damaged.
8. Pull spool (47) out of valve body (6) being careful
not to nick or scratch the surface of the spool. Remove
and discard seal (46) from groove in valve body (6)
bore.
Courtesy of Machine.Market