TM 5-3825-226-24
The oil from both sections of pump (22) goes to water
pump control valve (12). The oil from the drive end
section goes through line (10) to valve (12). Water
pump relief valve (14), with a pressure setting of
approximately 2500 psi (176 kg/cm 2) (17 250 kPa),
prevents high oil pressure damage to the parts in the oil
circuit from pump (22). The oil from the cover section
of pump (22) goes through water pump speed valve (6)
and adds to the pump oil in line (10) to water pump
control valve (12). With the engine running at high rpm
and the valve spool in control valve (12) in FORWARD
position (C), the oil from pump (22) goes through line (7)
to run water pump motor (1) at high speed. The oil from
the pump motor goes through line (8), control valve
(12), and through return oil line (13) into filter and tank
(19).
The water pump control lever must be moved to the
HOLD position to move the water pump valve spool to
HOLD position (B). With the valve spool in HOLD
position, the oil from pump (22) goes through control
valve (12), through return oil line (13) into filter and tank
(19).
WATER PUMP VALVES
Control Valve
The location of the water pump control valve is just in
front of transmission (2), near the left side of the
machine. The flexible cable from the control lever goes
under the water distributor hitch and is connected to
valve spool (1) in the water pump control valve.
WATER PUMP CONTROL VALVE
1. Valve spool (in control valve). 2. Transmission
Detent balls, in the control valve, keep valve spool
(1) in any of the three positions for the valve spool.
When the valve spool is held in FORWARD position
(C), the oil from the pump goes in through inlet (6),
opens check valve (7), goes through the check valve
and through outlet (4) that connects with an oil line to
the water pump hydraulic motor.
WATER PUMP CONTROL VALVE
(HOLD POSITION)
1. Valve stem. 3. Outlet to tank. 4. Outlet to motor
(for reverse). 5. Outlet to motor (for forward). 6.
Inlet from pump. 7. Check valve. A. REVERSE
position. B. HOLD position. C. FORWARD
position.
With valve spool (1) in HOLD position (B), The pump
oil through inlet (6) does not get any pressure to open
check valve (7) because the oil goes out through outlet
(3) and to the tank. The spring in check valve (7) keeps
it closed, when there is no pump oil pressure in the
control valve, and the oil in the lines to the water pump
motor is stopped. The hydraulic motor can not be
turned when oil is stopped in the lines to the motor.
With valve spool (1) in REVERSE position (A), the
pump oil through inlet (6) opens check valve (7) and
then goes through outlet (5) that connects with an oil line
to the water pump motor.
Speed Valve.
WATER PUMP SPEED VALVE
2. Transmission. 8. Valve spool (In LOW SPEED
position).
The water pump speed valve is beside transmission
(2) on the right side of the tractor. The flexible cable
from the water pump speed lever is connected to valve
spool (8) in the speed control valve.
5-6
