wheel RENAULT KANGOO 1997 KC / 1.G Chassis Repair Manual

ELECTRONICALLY CONTROLLED HYDRAULIC SYSTEMS
BOSCH ABS
38
HYDRAULIC BRAKING TEST
This section describes the test to be carried out using the XR25, to check the mounting of the ABS system in
the vehicle and, in particular, the hydraulic circuit.
NOTE: for this test, two persons are required and the vehicle must be on a two post lift, if possible.
Principle of the test
Put the vehicle on the lift with the wheel to be tested raised. One of the operators must be in the passenger
compartment in the driver’s position with the XR25. Switch the ignition on, vehicle in neutral, in fault finding
mode and press the brake pedal. The second operator must apply a torque to the wheel to try and rotate it.
The operator generates an appropriate command on the XR25 which carries out the following cycle ten
times: alternate decrease then increase in pressure at the wheel to be checked. These actions in the ABS will
be noted at the wheel as ten alternate locking and releasing operations. The jerky movement of the wheel,
noted qualitatively by the operator, signify that the hydraulic circuit for this wheel is correctly connected.
The programme for the XR25 for this sequence is as follows:
- Cycle on the wheel to be tested:
- a drop in pressure for 200 ms where the pump starts at the same time,
- an increase in pressure for 300 ms where the pump starts at the same time (ten cycles are carried out
for the wheel in question).
- The pressure increases to master cylinder pressure for all four wheels.
- The hydraulic pump motor stops.
- The operator releases the brake pedal.
The hydraulic test for the wheel in question is complete - begin the test for the three other wheels.
BLEEDING PROCEDURE
NOTE :
the hydraulic assembly is pre-filled.
This bleeding procedure must be used when one of the following components has been removed:
- the hydraulic assembly,
- the master cylinder,
- the pipework (between the hydraulic assembly and the master cylinder).
1)Bleed the braking system conventionally using the pedal.
NOTE : if, after a road test with ABS regulation, the pedal travel is not correct, bleed the hydraulic assembly.
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ELECTRONICALLY CONTROLLED HYDRAULIC SYSTEMS
BOSCH ABS
38
2)Bleeding the hydraulic assembly.
IMPORTANT : the bleeding order must be observed, beginning with the rear right , then the rear left, front
left and then front right.
a)Bleed the rear right brake by bleeding the hydraulic assembly secondary circuit using the XR25:
- position the bleed container and the hose, open the brake bleed screw,
- pump the brake pedal (approximately ten times),
- start the bleed command on the
XR25,
- pump the brake pedal during the diagnostic bleed phase,
- at the end of the bleed cycle on the
XR25, continue to pump the brake pedal and close the brake
bleed screw.
b)Carry out the procedure described at a) for the rear left, front left and front right brakes.
c)Check the pedal travel and if it is incorrect, restart the bleeding procedure.
IMPORTANT : ensure there is sufficient brake fluid in the reservoir.
CHECKING THE WHEEL SPEED SENSORS
a)Check the resistance of the sensor connections (from the computer connector to the 2 track speed sensor
connector).
b)Visually inspect the teeth ( 26 teeth) on the target and if they are faulty, replace the target.
c)Check the air gap using a set of shims. Only the front sensors can be checked.
PRN3820
Front: 0.13 < Z < 1.96 mm
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