four wheel drive RENAULT KANGOO 1997 KC / 1.G Chassis Workshop Manual

MECHANICAL ELEMENT CONTROLS
Braking compensator
37
Tooling required:
- one measuring tape mounted on a base (used
for measuring underbody heights),
- an accurate pressure gauge.
1• Preparation of the vehicle:
- the vehicle must be left loaded,
- the person in charge of pressing the brake
pedal when the compensator is being adjusted
must be in the vehicle when the radius under
load is measured at the rear wheels,
- the vehicle must be on a flat horizontal surface,
which is smooth and clean (use a four post lift if
possible).
2• Marking the centre of the rear wheels:
- lift the rear of the vehicle so the rear wheels
may be turned,
- apply a chalk stick to the hub cover or the
wheel embellisher at the approximate centre of
the wheel,
- turn the wheel by hand fairly quickly, pressing
hard on the chalk. This allows concentric circles
to be drawn around the real rotation centre of
the wheel,
- mark the centre using a pencil on the chalk,
- carry out the same operation on the second
rear wheel.3• Adjusting the rear tyre pressure:
- the pressure must be adjusted with the wheels
on the ground and one person in the driver’s
seat,
- deflate the two rear wheels so that the pressure
is brought to 1.2 bar (use an accurate pressure
gauge which has been correctly calibrated),
- wait a few minutes for the air in the tyres to
return to ambient temperature since it is
cooled when the tyres are deflated and the
pressure will therefore have changed,
- adjust the pressure to 1.2 bar as accurately as
possible.
4• Measuring the radius with the vehicle
unladen:
- lift the rear wheels so that the tyres are no
longer crushed by the load on the axle (as soon
as the wheels leave the ground),
- measure the distance between the ground and
the wheel centre using the measuring tape.
5• Measuring the radius with the rear wheels
loaded:
- return the vehicle to its wheels,
- measure the distance between the ground and
the wheel centre using the measuring tape.
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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.
38-9