Disc brakes are commonly found on the front wheels of automobiles and are occasionally found on the rear wheels as well. These are always self-adjusting in the sense that the friction pads are kept lightly rubbing against the disc to prevent free play. This cannot be used as an excuse for neglect, as the pads or shoes must be checked for wear on a regular basis.
Some discs are tapered when new, but flatten as they wear; replace the pads if the friction material is reduced to ⅛ in (3mm). Checking the disc brake pads is a simple task, though sometimes a retaining plate must be removed first by removing two retaining pins that are held in place by spring clips..
Brake drums are typically held in place by two small screws. With these out of the way, remove the brake drum and inspect the brake linings for wear. Drum brake adjusters are typically square pegs that must be turned with a special spanner until the brakes barely rub. Adjust the two cables’ equality if the handbrake is slack, even after the mechanism has been achieved using nuts at the operating lever.