18 - 2
Pressure Reducing Solenoid Valve
Removal
On machines prior to serial number 677001 the valve is
located under the driver’s seat. From serial number 677001
on the valve is located low down on the left hand side of the
engine bay.
Ensure that the engine is stopped.
!!
WARNING
It is not possible to vent all residual pressure. Loosen the
connection one full turn and allow the pressure to
dissipate. Keep face and hands well clear of pressurised
hydraulic oil and wear protective glasses.
HYD 4-3
Remove and plug all hydraulic hoses. Plug exposed
connections in the valve body 1. Disconnect the solenoid
electrical cables, making sure they are marked for correct
replacement.
Remove bolts X (2 off) and remove the valve.
Replacement
Replace bolts X and torque tighten to 12 Nm (9 lbf ft, 1.2 kgf
m).
Reconnect the solenoid valves and all hydraulic connections.
Dismantling
Secure the valve body 1 into a suitable soft jaw vice or
fixture. Remove the pressure reducing cartridge valve 2 and
the solenoid cartridge valve 3. Solenoids A and B can be
removed if necessary by unscrewing the coil retaining nut 4.
All seals and 'O' rings should be discarded. Do not
dismantle the cartridges.
If damage or excessive wear is found a cartridge should be
replaced as a complete unit.
The machined orifice in port 5 should be examined for wear
but not removed unless being renewed. Examine wiring for
damage or chafing; replace as necessary.
Assembly
Assembly is a reversal of the dismantling procedure. Fit new
'O' ring seals. Torque tighten to 23-28 Nm (17 - 21 lbf ft, 2.3 -
2.9 kgf m).
Check (and if necessary adjust) the setting of cartridge valve
2 (see below).
Replace solenoids on cartridge 3, apply a small amount of
JCB Threadlocker & Sealer to the coil retaining nut 4 and
torque tighten to 5 - 7 Nm (3.7 - 5.2 lbf ft, 0.5 - 0.7 kgf m).
Adjusting the Pressure Reducing Valve Cartridge
This cartridge should not be dismantled. If it malfunctions it
should be replaced by a new one.
Before checking the setting make sure the hydraulic oil is at
its correct working temperature.
To check the setting, connect a pressure gauge to the test
point which can be found under the floor plate on the brake
feed to either the left or right hand motor.
Note: On machines where the valve is located in the engine
bay, the test point was originally on the valve but was later
relocated on the left hand motor brake feed.
Ensure that the door is closed and the safety restraint is in
the operating position then start the engine and run at
maximum speed. Operate the arms lower service until the
rams are fully closed to ‘blow off’ the M.R.V. Check the
gauge reading which should show the regulated pressure.
See Technical Data for correct setting.
If the setting is incorrect, stop the engine. Remove the
cartridge dust cover C and adjust screw D to achieve the
required pressure. Replace dust cover C before restarting
the engine to recheck the pressure otherwise oil will leak
from the valve.
Section E
Hydraulics
9803/8500
Section E
18 - 2
Issue 5*
Valves
S205000
D
C
2
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