How do wedge brakes differ from S-cam brakes?
a.Wedge brakes use a wedge pushed between the brake shoes instead of an S-cam
b.Wedge brakes only work on front axles
c.Wedge brakes do not use air pressure
d.Wedge brakes are only used on trailers
Explanation
In wedge brakes, the brake chamber push rod pushes a wedge directly between the ends of the brake shoes, forcing them apart and against the brake drum. Unlike S-cam brakes, they do not use a slack adjuster or S-cam mechanism.