Main Control Valve Repair
REMOVE
WARNING
Lower carriage completely before working on con-
trol valve or hydraulic system. DO NOT work un-
der a raised carriage. Put mast in a vertical posi-
tion, with no forward or back tilt, and lower car-
riage completely before disconnecting any parts
of hydraulic system. The mast can lower suddenly
and cause injury if the carriage is not lowered.
NOTE:
Most of the individual valve components
can be removed and replaced while the control
valve is installed in the truck. Removal of the con-
trol valve for repairs is normally only required to
replace a valve section, or to replace the O-rings be-
tween the sections.
1.
Power wash the interior of the operator com-
partment to remove any dirt or debris.
2.
Move truck to disassembly area and shut off en-
gine.
WARNING
Cleaning solvents can be flammable and toxic and
cause skin irritation. When cleaning solvents are
used, always follow the solvent manufacturer’s
recommended safety procedures. Wear protective
goggles or a face shield to prevent eye injuries.
WARNING
Be careful when cleaning with steam. Steam can
cause serious burns. Wear protective clothing,
gloves, and eye protection. Never expose your
skin to steam.
NOTE:
Take all necessary steps to prevent debris,
dust, or other contaminants from entering the valve
cavities, hydraulic lines, or replacement parts.
3.
Remove the floor plate, kick panel, seal plate,
and dashboard. See Frame 0100SRM1891 for
the procedures.
4.
Before disconnecting any hydraulic hoses or re-
moving any parts from the control valve, clean
the outside of the valve either by steam clean-
ing or with cleaning solvent.
5.
To remove the accelerator pedal or MONO-
TROL
®
pedal assembly, disconnect the cowl
wiring harness from the pedal assembly wiring
harness and remove three mounting capscrews.
See Figure 3.
NOTE:
To aid in installation, tag all connectors
prior to disconnecting from the solenoids.
6.
Disconnect the cowl wiring harness from the
top auxiliary function Proportional Pressure
Reducing Valve (PPRV) solenoids. See Figure 4.
NOTE:
ACCELERATOR PEDAL NOT SHOWN,
HOWEVER, REMOVAL IS THE SAME.
1. MOUNTING CAPSCREW
2. MONOTROL PEDAL ASSEMBLY
3. PEDAL ASSEMBLY WIRING HARNESS
Figure 3. MONOTROL Pedal Removal
2000 SRM 1899
Main Control Valve Repair
3