Chery QQ - Testing for the Braking System

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.
6
Chery Automobile Co., Ltd