Operation and maintenance manual

Section 250-0045
1
SM 2162 8-02
DESCRIPTION
Numbers in parentheses refer to Fig. 1. The motor/
triple pump (1) can be identified as item 7 in Section
210-0005, COOLING SYSTEM SCHEMATIC.
Mounted off brackets 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
hydraulic motor within the assembly is protected by a
relief valve (2).
OPERATION
Numbers in parentheses refer to Fig. 1.
Refer to Fig. 2. The motor is supplied with hydraulic oil
from the brake cooling section of the triple gear pump,
via the disc brake oil cooler. 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. Cooling oil is then
pumped to low pressure relief valve, before being
supplied to brake packs. Refer to Section 210-0046,
LOW PRESSURE RELIEF VALVE.
A sealing arrangement within the assembly prevents
cross contamination of hydraulic oil from triple gear
pump with brake cooling oil from brake coolant tank.
The relief valve (2) limits the pressure through the
motor to 100 bar (1450 lbf/in
2
).
Note: Direction of rotation is clockwise as viewed from
shaft end, and is indicated by an arrow.
REMOVAL
Numbers in parentheses refer to Fig. 1.
WARNINGS
Hydraulic fluid pressure will remain within the
system after engine shut down. Operate the
treadle valve continuously until the pressure
has dissipated before carrying out any work on
the braking system or serious injury could
result.
To prevent personal injury and property
damage, ensure wheel blocks, blocking
materials and lifting equipment are properly
secured and of adequate capacity to execute
the job safely.
BRAKING SYSTEM - Motor/Triple Pump Assembly
SM - 2761
1 - Motor/Triple Pump
2 - Relief Valve
3- Bolt
4 - Washer
5- Nut
6 - Rubber Plate
7- Bolt
8 - Lockwasher
9- Washer
10 - Rubber Plate
Fig. 1 - Motor/Triple Pump
SM - 2762
Fig. 2 - Motor/Triple Pump Schematic
T
O HYDRAULIC
TANK
FROM BRAKE
COOLANT TANK
FROM DISC BRAKE
OIL COOLER
TO LOW PRESSURE
RELIEF VALVE
1. Position the vehicle in a level work area, apply the
parking brake and switch off the engine.
2. Block all road wheels and place the battery master
switch in the 'Off' position. Place steering lock bar in
the 'Locked' position.
3. Remove blanking cap from remote drain line at the
bottom of the hydraulic tank. Install a length of hose on
remote drain fitting, open drain cock and drain
hydraulic oil into a suitable container. Close drain
cock, remove hose and reinstall blanking cap.
1
10
3
4
5
6
7
8
9
2