Operation and maintenance manual

Section 210-0005
Cooling System - Brake Cooling System Schematic
SM 2154 Rev 1 10-03
2
CHECKING SYSTEM PRESSURE
WARNINGS
To prevent personal injury and property
damage, be sure wheel blocks and blocking
materials are properly secured and of adequate
capacity to do the job safely.
1. Ensure that hydraulic oil has reached operating
temperature, position the vehicle in a level work area
and apply the parking brake. Block all road wheels.
2. Connect a hydraulic gauge, capable of recording a
pressure of 0 - 345 bar (0 - 5 000 lbf/in²), to diagnostic
check point at brake cooling section of triple pump.
3. Increase the engine speed to 2 200 rpm and note the
reading on the gauge. Pressure should be 110 bar
(1600 lbf/in²).
4. If pressure is low, triple pump should be checked.
Refer to Section 250-0040, TRIPLE PUMP.
5. Shut off the engine and remove the pressure gauge
from triple pump. Remove wheel blocks.
'O' RING FACE SEALS (ORFS)
Where hydraulic lines are fitted with ORFS
connections, the following procedure should be carried
out during installation. Refer to Fig. 1.
a. Ensure 'O' ring/seal is in place and that joining
surfaces are clean. If necessary, retain 'O' ring/seal in
place with a light coating of grease or vaseline.
b. Initially, the nuts should be tightened by hand.
c. Where a hose is fitted, ensure that it is not twisted
or kinked when the nuts are tightened so that it is
allowed to adopt a natural position.
d. Where a tube is fitted, ensure that the connection is
aligned correctly.
e. Tighten the nut a further 1/4 to 1/2 a turn using the
correct size of spanner (wrench).
f. Check that a satisfactory hose or tube routing has
been achieved.
Mounted on the disc brake oil cooler casing on the right
hand fender, the two speed control valve regulates the
fan speed of the disc brake oil cooler. The two speed
control valve is supplied by the rear section of the triple
gear pump (1), via pressure relief valve (4).
Disc Brake Oil Cooler (6)
Refer to Section 210-0050, DISC BRAKE OIL
COOLER.
The disc brake oil cooler is mounted on the right hand
fender adjacent to the main hydraulic tank. The fan
within the brake oil cooler is driven by a hydraulic
motor. The speed of the fan is dependant on the oil
flow being supplied to the motor from the two speed
control valve (5).
Brake cooling oil enters the top of the cooler and flows
through the cooler before exiting at the bottom. There
are three inlet ports and three outlet ports, one for each
axle.
Motor/Triple Pump Assembly (7)
Refer to Section 250-0045, MOTOR/TRIPLE PUMP
ASSEMBLY.
Mounted on the left hand frame rail, adjacent to the
brake coolant tank, the motor/triple pump assembly
consists of three pump elements coupled to a single
direction hydraulic motor.
The motor is supplied with hydraulic oil from the rear
section of the triple gear pump (1), via the disc brake
oil cooler (6). The motor and pump elements are
connected by a common shaft, therefore motor rotation
causes pump elements to draw brake cooling oil from
brake coolant tank (2). Cooling oil is then pumped to
low pressure relief valve (8), before being supplied to
brake packs.
Low Pressure Relief Valve (8)
The low pressure relief valve, mounted on the brake
coolant tank (2), ensures that only low pressure cooling
oil is supplied to the brake packs. There are three
pressure relief valves housed in valve, one for each
axle, which are set at 1.5 bar (22 psi).