Section IV. HYDRAULIC CONTROL VALVE

TM 10-3930-632-34

specifications at rated test pressure. Allow t 10 percent

NOTE

flow gage tester tolerance when comparing recorded

It will be necessary to maintain engine speed of

readings to specifications. Recorded readings that are

1450 RPM when testing-pump under load.

consistently below specifications indicate that pump is

worn and should be repaired or replaced.

After recording flow reading at 100 PSI,

k. Disconnect test lines and tachometer. Connect

gradually apply load valve (turning clockwise) until

hydraulic pump pressure line to pump and reservoir

pressure stabilizes at 1000 PSI. With flow gage needle

return line to hydraulic control valve.

stabilized, record flow reading at 1000 PSI. Flow reading

should be 5 GPM or slightly higher.

Pump output should be reasonably close to

Section IV. HYDRAULIC CONTROL VALVE

4-15.

General

4-16.

Removal

Disconnect the hydraulic lines from the

The hydraulic control valve includes two separate valve

sections joined together with bolts and nuts. One section

hydraulic control valve (TM 10-3930-632-12). Plug all

controls the operation of the lift cylinder while the other

open ports to prevent the entry of dirt.

controls the operation of the tilt cylinders. Each section

Remove the control linkage.

consists of a close-fitting spool which is installed in the

Remove the capscrews, nuts and lockwashers

bore of the body. The lands and grooves on the spool

that secure the hydraulic control valve to the lift truck;

direct the flow of the pressurized hydraulic fluid to

remove the hydraulic control valve.

operate the associated cylinder. Check valves are

installed to prevent reverse flow of fluid. A relief valve is

4-17.

Disassembly

installed to relieve excess system pressure.

Refer to figures 4-4 and 4-5 and disassemble the

hydraulic control valve sections. Note the following:

4-7