BC Transit – Air Brake Course

Wedge Brakes
This type of brake uses one or two small air chambers with
wedge-shaped pushrods. Once quite common on drive and
trailer axles, wedge brakes are now usually found only on
steering axles.
When the brakes are applied, air pressure in the brake
chamber pushes the wedge part of the pushrod between two
rollers, forcing the brake linings out to contact the brake
drum.
Unlike conventional s-cam braking systems, drivers cannot
easily check the wedge brake adjustment. While most
wedge brakes have internal automatic adjusters, if the wedge
brakes need to be checked for adjustment, or repairs are
needed, only a qualified mechanic should carry this out.
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