Reinventing the brake

Reinventing the brake

Nearly a decade ago, the EPA outlawed using asbestos in commercial products — the result is a decade of brake product improvements

By Greg Napert

April 1998

It wasn't very long ago that the Environmental Protection Agency (EPA) outlawed the production of any products incorporating asbestos. The EPA's Asbestos Ban and Phase-out Rule, which was implemented in 1989, as well as the National Emission Standards for Hazardous Air Pollutants (NESHAP) rules implemented in 1990, eliminated the production of products that contain asbestos. The laws allowed brake pad suppliers to sell the remaining products they had in stock but not manufacture any new ones with asbestos as an ingredient.

Unfortunately, asbestos was the primary ingredient, as it is resistant to heat and is also flexible enough to resist cracking.

The new laws sent the brake pad manufacturers and suppliers scurrying off to find a replacement material that could be used for brake pads.

Cleveland Wheels and Brakes was the first to introduce a non-asbestos replacement material that it uses to this day. John Bakos, distributor sales manager for Cleveland and Airborne, says that the company has been using the product ever since they introduced it in 1988, and it has performed quite well. Like the asbestos pads, he says, they still have to be conditioned properly in order to work as they should.

Other manufacturers, such as Rapco in Hartland, WI, had some growing pains with the replacement material. Many problems were primarily with cracking of the pads. Although cracking was often the result of placing too much pressure on the rivets during installation, the material should have been able to hold up to traditional brake pad installation techniques. Rapco continued to experiment with new combinations of materials to replace asbestos.

Pat White, VP of sales and marketing for Rapco, explains that the company continued to invest in research with new materials that would perform as well as asbestos. Nine years and several brake pad generations later, the company is finally satisfied with the material it's using. In fact, they believe the new formula for their pads is better than asbestos.

Mike Lotzer, sales manager for Rapco, says, "The material we are using today is as good as the original asbestos in terms of its performance. I believe the new material will actually outlast the original."

Lotzer explains, "The first replacement material we used after asbestos was outlawed did quite well on the dynamometer, but there was a consideration that we didn't take into place — it was too brittle in operation. Asbestos was a much better material for binding and flexing. The new material was brittle, and many people were cracking the linings upon installation, or they would crack if the disc or back plates were not perfectly flat. So we discontinued that lining. We then changed the material and added a metal back plate. We still weren't satisfied, so we moved to encasing the material in aluminum to try to prevent cracking. As time progressed, we finally discovered a material that was quite good, and this allowed us to eliminate the backplates."

With the exception of Cleveland's brake lining material (Cleveland does not use Kevlar in its linings), one component of the newest generation of brake pads is Kevlar, a fiber commonly found in many of today's composites, including bulletproof flack jackets.

Jeff Kelly, president of AVPRO, says his company introduced a specially designed Kevlar-based non-asbestos organic brake linings, which offer many improvements over non-asbestos pads available in the marketplace today. "The primary improvement is a 25 percent service life increase over non-Kevlar pads with no reduction in the coefficient of friction or otherwise stated braking power. This means for every four non-Kevlar lining changes, you will only need to provide three AVPRO changes."