Section II. CONTROL VALVE

TM 10-3930-631-34

screws (5, fig. 7-2) are installed directly opposite the

(13)Install port adapter (16) and new gasket (17)

twelve point screws (fig. 7-3). Tighten all screws to a

on adapter (18) and secure with screws (14) and lock

torque of 25 to 28 pound feet (3.4-3-8 m-kg).

washers (15). Tighten screws to a torque of 10 to 12

pound feet (1.38-1.73 m-kg).

(14)Coat new seal (30) liberally with oil (OE).

Place tape over splines on drive shaft and install seal

(30) in front plate over shaft. Install seal carefully to

prevent damage to oil seal lip.

(15)Rotate pump shaft by hand or with pliers.

Shaft will have small amount of drag but should rotate

freely after a few turns.

e. Installation. Refer to paragraph 2-13 and install

hydraulic pump. Before operating hydraulic system,

check pressure and adjust control valve relief valves as

described below.

Figure 7-3. Pump screw location.

Section II. CONTROL VALVE

Pressures are preset but should be checked at regular

7-3. Pressure Adjustment

intervals and whenever control valve or hydraulic pump

a. Description.

has been replaced or repaired.

(1) Two relief valves are incorporated in the

b. Low Volume Pressure Adjustment.

control valve.

One controls the low volume inlet

(1) Disconnect battery receptacle and discharge

pressure. The low volume pressure is used in the tilt and

capacitors. Remove sheet metal cover and floor plate to

side shift circuits. The other relief valve controls the high

gain access to hydraulic control

volume pressure used in the lift circuit. Relief valves

valve.

protect the hydraulic system from excessive hydraulic

(2) Remove pipe plug from large plug in side of

pressure.

inlet section. Install a pressure gage with a zero to 3000

(2) Whenever a cylinder reaches full stroke

psi (0-210.9 kg-cm2) range. A short length of high

position or when an excessive load is handled, hydraulic

pressure hose may be installed between gage and valve

pressure will build up to beyond safe limits. This

to facilitate installation of gage (fig. 7-4).

pressure opens relief valves and bypasses the hydraulic

oil to the reservoir.

7-6