Premature Front Pad Wear
on Four-Wheel-Disc Passenger Cars
Passenger cars that use four wheel disc brakes usually
rely upon parking brake application to maintain the
correct clearance between the rear disc-brake pads and
the rear rotors. Because customers frequently are not
in the habit of applying the parking brake every time
they stop the car, the clearance between the pads and
the rotors becomes excessive after a period of time.
When this happens, the rear brakes do not do the portion
of the braking that they are designed to do and premature
front pad wear occurs.
This premature front-pad wear is particularly evident
after the front brakes alone are relined. This pad wear
will occur regardless of whether the rotors and callipers
are rebuilt or replaced. The solution to the problem
is to educate your customers to use the parking brake
on a regular basis. Modern parking brake cables are
protected from corrosion and binding and generally do
not freeze up as the parking brake cables of years ago
did. If the customer has not been in the habit of using
the parking brake, it may take as many as 40 to 50 applications
of the parking brake to obtain the proper clearance
between the disc-brake pads and the rear rotors.
Also, it is a good idea to maintain some lubrication
between the parking brake cables and the outer case
even though the cables may be encased with a protective
coating. It has become acceptable to use a synthetic
or silicone grease in the area where the parking brake
enters its shield casing. Synthetic or silicone grease
does not attract dirt or moisture and will maintain
a free parking brake situation throughout the life of
the car if done on a periodic basis.
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