Brake Complaints?

Squealing, squeaking, grinding and steering wheel vibration while braking at highway speeds?

Shorter service life and black soot on the finish of your wheels?

Every service center, be it new car dealer, independent service or brake specialty center, is plagued with these complaints.

Most of today's brake systems consist of four rotating metal discs that are fixed just behind the wheels. There is a fixed device caller a caliper saddling each of the brake discs that compress two pads up against the rotating discs. The brake pad is made of an expansive friction material. The early brake pads were made of a mixture of asbestos fiber and soft metals and glue, which expanded quite efficiently at about 250 to 500 degrees. The soft material was very forgiving to the entire brake system. Asbestos is no longer available because of Federal regulation of hazardous substances.

Squealing happens when two smooth surfaces rub together creating a very fast vibration or resonance. The most common cause is light braking which tends to polish the brake disc and pad surface, lending to resonance, especially at very slow speeds. Contaminants or oil on the friction material can also create resonance. The day after the first rain of the season, we are inundated with complaints of brake noise. Vehicle age and condition can also lend to brake noise. Loose or worn suspension components allowing the fixed brake calipers to vibrate can cause resonance or brake noise.

It's too bad we can no longer use asbestos as a friction material, it worked so well. As a brake material it was completely consumed, creating no hazard to the vehicle operators. The hazard was to the manufacturer and mechanic installer. I am all for federal regulation to protect our health, but I can't believe all that black soot generated by carbon brake pads is not a health problem.

Today's carmakers use a very hard carbon like material that requires a much higher temperature to expand, about 400 to 900 degrees. The first problem is heat. Heat causes the rotating discs to change shape, which creates brake pedal pulsation and steering wheel shake when the brakes are applied. The high temperature can also shorten the service life of the wheel bearing and hydraulic brake calipers, hardware and return springs. The hard carbon material wears away at a high rate while "grinding" away metal from the brake disc. Some vehicles require brake disc replacement at every brake service and brake service may be required as soon as 12,000 to 20,000 miles, depending on the type of driving the vehicle is subjected to.

Dirty black wheels- that's the brake pad dust building up on the surface of your aluminum wheels. That same black dust is what plugs up the in car filters on cars that are equipped.