From: utzoo!watmath!watcgl!dmmartindale Newsgroups: net.auto Title: Re: Backing up to even out brakes Article-I.D.: watcgl.182 Posted: Wed Feb 9 11:54:35 1983 Received: Thu Feb 10 00:19:57 1983 References: alice.1473 As Keith Bauer explained, disk brakes are self-adjusting because as the pads wear, more fluid from the master cylinder reservoir takes up the extra volume in the wheel cylinder. Since the pressure on the pads is applied solely by the hydraulic cylinders, this is enough to handle all the wear that occurs. In drum brakes, the shoes are supported at two points - one at each end. One of these is the hydraulic cylinder, and the same sort of automatic adjustment takes place here as with the cylinder in disk brakes. The other end, though, is supported by a mechanical stop of some sort, and this also has to be adjusted to compensate for wear of the shoes. Various manufacturers do different things to provide this adjustment. Some cars have no automatic adjustment at all, so the adjustment is done manually from time to time. Many of the American cars use a mechanism where when you apply the brakes while backing up and the shoes move more than a certain amount, a cable tightens and rotates an adjusting nut a fraction of a turn. If you stop while backing up occasionally and the mechanism stays working, the brakes stay adjusted. The method that works on your car depends on how the manufacturer designed the brakes - there is nothing magic about backing up and applying the brakes. Dave Martindale