It can be difficult to pass up a trailer full of brake components that are offered at a bargain-basement price. Cost-conscious customers may be more than willing to try some unknown friction material for trailers of their own, or even save a few dollars by spec’ing unfamiliar wiring.
In the end, however, there is always a price to be paid – and it can emerge in the form of limited service life and longer stopping distances.
Those who supply premium aftermarket brakes point to a lack of standards as one of the problems, noting how original equipment on a new trailer must conform to the federally regulated rules of FMVSS 121, while an aftermarket lining can be made from a variety of materials with dramatic differences in quality and performance. For instance, a simple FF (lining edge code) pad can be made from 20 different materials, and each of them will offer different performance characteristics, says Jim Vigliano, ArvinMeritor’s director, fleet sales.
Today’s comparisons are largely limited to the independent ratings posted by the Society of Automotive Engineers’ Performance Review Institute (www.pri-network.org), which measure the torque delivered by 40-psi brake applications.
“It attempts to give you some indication of how they stack up,” says Randy Petresh, Haldex’s vice-president of technical support. The Technology & Maintenance Council of the American Trucking Associations only now is considering whether the tests should expand beyond common 16.5 x 7-inch material, and include details about factors such as a manufacturer’s quality certificates, the presence of asbestos and the country in which the linings are made.
Counterfeit offerings have emerged among other brake components as well. Haldex, for example, has identified numerous copies of its automatic slack adjusters. Bendix has seen copies of valves that are packaged to look like the genuine articles.
Appearances can be more than just deceiving, and the quality of the product must be considered. Thinner valve walls can lead to cracks or ruptures. Inconsistent tension in the springs can turn a valve into little more than an on-off switch, eliminating any hope of a gentle brake application. Stiff O-rings quickly will lead to air leaks.
