Check of front disc brakes
P-10
Check of front disc brakes
Introduction to the repair tips of brake judder
There are three features as shown below in the problems of brake judder:
(1) Vibration of steering wheel. The steering wheel vibrates in the direction of rotation and such feature is
the most notable when braked at the speed between 100～140 km/h {62～87 mph};
(2) Floor vibration. In braking, the bodywork vibrates forward and rearward, and the vibration intensity is
not subject of the speed effect;
(3) Vibration of brake pedal. When the brake applied, there is impulsive force trying to push back the brake
pad, and transferred on the brake pedal.
The followings are some key raisons possibly resulting in brake judder:
When the brake disc jittered too much, the swing thickness between the one side and another is uneven. If the
judder is over 0.05 mm {0.002 in} at 10 mm {0.39 in} away from the edge of brake disc, it means the uneven
wear on the disc occurred due to the contact of the unbalances of pad and disc, if it is less than 0.05 mm
{0.002 in}, it means that no uneven wear occurred.
Thermal deformation of disc The repeated violent brakes may enable the disc local temperature to increase up
to about 1000℃ {1832ºF}, resulting in the disc distortion.
The thickness and friction coefficient of disc will change due to corrosion. If the vehicle parked for longtime
in wet condition, the friction surface of disc will be corroded. When the corrosion thickness is uneven, it will
take the corrugated shape, resulting in the variation of friction coefficient and the reaction force.
Check and repair process
Check the lateral run-out
1. Screw up, in crosswise, the hub nut to assure that the disc and hub properly were installed or the washer
inserted between the hub bolt and hub nut with the spacer thickness in10mm {0.39 in} and the I/D more
than 12 mm {0.47 in}.
Note:
The part composed by SST 49 B017001 or 49 G019 003 may be use as the suitable washer.
Identify the complains of clients
Carry out the radial run-out check
Refer to Radial Run-Out Check
Less than
0.05mm
(0.002)
Less than 0.05mm
(0.002)
C
onfirm whether there have
been any brake jitters
reinstall at another phase and
make again the radial run-out
check.
heck the thickness variation
below)
Verify the repair
se the mold on the vehicle to
process the disc plate
Tighten all rim nuts by the same
torque to fix the brake disc and
measure the radial run-out.
More than 0.015mm (0.0005in)
0.05mm
(0.002in)
se the mold on the vehicle.
[Less than 0.015mm (0.0005in)]
Work completed
Not presented
More than 0.05mm (0.002in)
To Next Page
Loading...