Brake system mechanical detailing

["Warren R Anderson" <wranderson@xxxx>]

Group:

I would like to share a few handy tips concerning brake mechanicals. Some of
these items are showing up in current factory fix bulletins from the OE
people and in professional tech group postings so I think it is timely to
make mention..

Brake friction surfaces must be free of contaminants; dirt, grease,
solvents, etc. The recommended procedure to clean is hot soapy water and
rinse. Aerosol brake cleaners alone are not recommended.

The materials in brake pads and shoes that are on the shelf today should not
be of asbestos content. Without the availability of proper breathing
protection equipment, a thorough soap and water wash down of the brake
assembly prior to disassembly is the best way to keep brake dust of any kind
out of the air.

I like to replace all the brake parts I take off to do a brake job with new
on an old car that I intend to drive. It is very important that a very
careful inspection be made of the backing plate (drum brakes) or caliper
mounting surfaces. It is critically important that backing plates shoe
mounting surfaces must be very flat, smooth and in a plane. These surfaces
can be repaired (usually). Calipers are of many designs and there may not be
a decision to fix or replace. The worn out caliper mounts I have
encountered, replacement was the only fix.

Even a small pit in a wheel cylinder (or master cylinder) bore will cause a
leak. Any corrosion you can SEE will cause cylinder failure and ruin a good
brake job. I have, therefore, given up trying to kit wheel cylinders and
especially master cylinders (even in our dry climate). Sleeves or new will
work; honing and honing and honing will not. With new, watch out for NOS as
rubber may (will) need replacement even though cylinder has never been in
service.

ANY drum must be trued and resurfaced when new linings are installed. A
minimum amount of metal should be removed. With old drums, braking surfaces
must be ground to smooth (but not remove) hot spots. Soap and hot water and
a scrub brush should be used to clean drums or rotors after machining (not
aerosol cleaners).

ANY rotor needs truing and resurfacing with new pads. Most brake techs are
using small diameter low RPM sanding discs to put a swirl pattern on the
braking surfaces.

A lot of really bad stuff will collect in a caliper. In our neck of the
woods, we do not have a rust problem. We still think real hard about caliper
overhaul at 60K and definately do the job at 90K +.

Brake pad/ shoe friction material will vary greatly. Cheap 'Auto Zone' will
not get the job done. Premium lining material should be sourced. I know it
can be custom installed on old shoes because I have had it done and it does
make a big difference and is not costly. Shoes need to fit the drum. Watch
out for below max diameter drums and oversized shoes to fit oversize drums.

Warren Anderson
Sedona,AZ