Operation and maintenance manual

Braking System - Triple Pump
Section 250-0040
SM 2157 8-02
2
SM - 2764
SM - 338
DRIVE GEAR
OUTLET
INLET
DRIVEN GEAR
Fig. 2 - Typical Pump Operation
Fig. 3 - Hydraulic Schematic of Triple Pump Operation
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.
4. Clean pump housing and tag and disconnect inlet
and outlet lines from the pump. Drain oil in lines into a
suitable container. Cap lines and pump ports to prevent
ingress of dirt.
5. With suitable blocking or lifting equipment, support
pump before loosening mounting bolts (5). Remove
bolts (5) and washers (6) and lift pump clear. Move
pump to a suitable work area for 'Disassembly'.
DISASSEMBLY
Numbers in parentheses refer to Fig. 1.
1. Place pump in a soft-jawed vice, driveshaft (10)
down. Match mark all pump sections to aid assembly.
Note: Do not clamp vice on pump machined surfaces
at any time.
2. Note location of all hydraulic connectors and
adaptors and remove from triple pump.
3. Remove bolts (16) and washers securing front pump
housing (12) to rear pumps (15).
opposite direction. The pockets between the gear teeth
carry oil from the inlet port around the gear housing ID
to the pump outlet port. As the gear teeth re-mesh,
this oil is forced out of the outlet port of the gear
housing. The maximum oil delivery rate of each section
of the triple pump is fixed by the width of its respective
gear set and the speed at which driveshaft (10) is
turned.
Maximum delivery of front section = 59 litres/min.
Maximum delivery of middle section = 43 litres/min.
Maximum delivery of rear section = 19 litres/min.
The triple pump draws oil from the hydraulic tank, then
pumps the oil to supply the various circuits. The triple
pump is assembled for left hand (anticlockwise)
rotation, as viewed from the driveshaft end.
REMOVAL
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.
1. Position the vehicle in a level work area, apply the
HYDRAULIC TANK
TO ENGINE
COOLING CIRCUIT
TO BRAKE
CIRCUIT
TO BRAKE
COOLING CIRCUIT