Taper Check

An out-of-round or tapered drum prevents accurate brake shoe adjustment, and is likely to cause excessive wear of other brake parts due to its eccentric action. An out-of-round drum can also cause severe and irregular tire tread wear, as well as causing the brake pedal to pulsate. When a drum exceeds specification limits in taper and/or out-of-round, refinish the drum to true up the braking surface. Out-of-round, as well as taper and wear, can be accurately measured with an inside micrometer and extension rods. When measuring the drum, take measurements at the open and closed edges of the machined surface and at right angles to each other.