Chery S11 / Chery QQ. Manual — part 23
Chery QQ Service Manual Chassis System
Step
Operation
Normal outcome
Abnormal outcome
1
Check the liquid level of
the brake liquid inside
the oil storage tank
At normal height
Too low
2
Turn off the ignition
switch
Make sure the static
brake is loose
Activate the engine
The alarming indicating
light is on when the engine is
activated.
The light is on when the
engine is activated, but it
goes off after the engine is
started.
The light is not on when the
engine is activated.
The light is on after the
engine is started.
3
Step the brake pedal to
the extreme
The pedal moves stably
toward the floor.
The pedal stops and resists
the pressure.
The pedal moves unsteadily;
The pedal is too soft or too
close to the floor.
4
Release the brake pedal The pedal returns to its
original position.
The pedal fails to return to
the original position.
5
Test the hydraulic brake
system
The braking action is
immediately operated when the
pedal is stepped.
The operation of the brake
is smooth and normal without
any blocks and vibration of
the pedal.
The steering wheel and the
brake pedal do not vibrate
when the pedal is stepped.
The car stops without using
too much force in stepping the
pedal.
The car moves steadily
forward
during
braking
operation.
The front and rear brakes
work simultaneously.
The brake does not have much
operational noise.
The brake does not delay in
reset after the pedal is
released.
The braking action delays
after the pedal is stepped.
The brake works roughly when
the pedal is gently stepped.
The steering wheel or the
brake pedal vibrates when the
pedal is stepped.
It is hard to step the pedal
and to stop the car movement.
The car moves toward one side
when the brake is applied.
The front brake and the rear
brake work unevenly.
There is much operational
noise of the brake.
The brake delays to return to
the original position, after
the pedal is released.
To verify the outcome of the tests, make comparisons between the verified
outcomes with those of the car/system of the same model in operation.
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Chery QQ Service Manual Chassis System
Refer to the related fault diagnosis table for the operational outcome.
2) External factors that have imp-
acts upon the braking performances
Tires
The differences of the contacts
with the road surface as well as the
differences in adhesion forces for
various tires may lead to the
differences in braking performances.
Under the following circumstances,
some unfavorable impacts might be
caused to the braking performance.
Difference in the sufficiency of
air filling to the tires;
Difference in tire sizes;
Differences in tire surface
patterns
Vehicle loads
Heavier duty vehicles need
larger braking forces. For the
vehicles with uneven loads, the wheel
subject to the maximum loads needs
larger braking force than the other
wheels.
Wheel positioning
The tests for the braking system
should be made on the road surface
meeting the following conditions.
3) Tests for the braking system
The tests for the braking system
should be made on the road surface
meeting the following conditions.
Dry
Clean
Properly leved
Horizontal
The tests are not to be made on
the following road surfaces, because
the tires will not evenly adhere to
the ground surface.
Wet
Slippery
Covered with soft and loose soil
If the road surface bulges, which
makes the load weight lopsided toward
the wheels on one side, unfavorable
impacts will be caused to the tests.
If the road surface is not leveled,
which makes the wheel bounce and jump,
unfavorable impacts will also be
caused to the tests.
Under different car speeds, the
tests on the braking system can be
made by way of the brake pedal forces
for the point braking and abrupt
braking. It is advised not to apply
the brake in a steady-firm way or to
make the tires slip by towing. The
braking distance for the wheel
rotations in the action of abrupt
braking will be shorter than the one
for the dead movement of the wheels.
Therefore, the deadly applied brake
and the slipping tires cannot truly
reflect the braking performances and
efficiency.
Unless under extreme speed
reduction, the brake system needs to
be balanced so as to avoid the hard
feelings of the brake pedal when
abrupt and dead braking action is
applied.
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Chery QQ Service Manual Chassis System
4) Stroke of brake pedal
The excessively short stroke of
the brake pedal is mostly caused by
the action of the air inside the
braking system. Discharge the air
inside the system until all the air
is discharged completely. Refer to
the “Air Discharge for Hydraulic
Systems” for more details. The
reasons uncommonly seen to cause the
excessively long stroke of the brake
pedal are as follows:
Excessive tears and wears of the
friction lining
Leakage in the hydraulic system
Make regular and periodic
measurements of the brake pedal
strokes, which refer to the distances
for the pedal to move from a
completely released position to the
floor.
5). Braking liquid leakage
Leave the engine in idle running
operation and leave the transmission
shaft at the “idle gear” position.
Step on the brake pedal and keep the
stepping force unreplaced. If the
pedal is lowered slowly under the
unreplaced force, it means there
might be leakage in the hydraulic
system. Make the following visual
checks to see if there is any leakage:
Check the liquid level inside the
main pump liquid storage tank of
the braking system. Normal tears
and wears of the friction lining
will lead to the slight lowering of
the liquid level in the storage
tank. If the liquid level is too
low, it will cause the brake
alarming indication light to be on,
which means there might be
internal or external leakage for
the hydraulic system.
Check to see if there is any
leakage at the joints of the
braking pipe and the braking tube.
Check the torque of the fastening
parts or replace the oil pipe and
tube.
Check to see if the components
connecting the brake are damaged
or not. Replace the components if
needed.
Check to see if there is any
leakage at the protection cover of
the clamp and wheel cylinder. If
any, replace the parts as needed.
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Chery QQ Service Manual Chassis System
II.Guide to the maintenance of hydraulic brake
1.The master pump of the braking
system
1). Refilling of the liquid storage
tank for the master braking pump
Warning: Do not fill in the liquid excessively,
which may result in the overflow of the braking
liquid to the engine or other parts of the front
cabin during the operation of the braking system.
The braking liquid is corrosive and combustible
in nature, which may cause corrosions to the
other parts and components. If it contacts with
the air exhaustion system of the engine, it might
lead to fire hazard or human injuries.
The liquid storage tank and the
master pump are connected and sealed
by way of sealing rubber sheath,
fastened with screws. The liquid
storage tank is located at the left
side of the car and under the engine
cabin cover. Sufficient level of
braking liquid should be maintained
in the tank of the master pump.
Therefore, under normal conditions,
the liquid storage tank does not need
maintenance. When the braking liquid
level inside the storage tank is
excessively low, the liquid level
sensor will make the timely alarming
signal.
Refilling of braking liquid
Clean the outer surfaces before
opening the cover of the liquid
storage tank so as to prevent the dust
from entering the tank.
Open the screwed cover
The refilled liquid should not
exceed the maximum liquid level
inside the tank
Re-install the screwed cover
2) Replacement of the liquid storage
tank of the master pump
1. Remove the wire plug of the
liquid level sensor of the storage
tank;
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