Inspection - Rear Drum In Hat Brake

Fig 1: Brake Shoes

Courtesy of DAIMLERCHRYSLER CORP.

As a general rule, riveted brake shoes should be replaced when worn to within 0.78 mm (1/32 in.) of the rivet heads. Bonded lining should be replaced when worn to a thickness of 1.6 mm (1/16 in.).

Examine the lining contact pattern to determine if the shoes are bent or the drum is tapered. The lining should exhibit contact across its entire width. Shoes exhibiting contact only on one side should be replaced and the drum checked for runout or taper. See Fig 1.

Inspect the adjuster screw assembly (6). Replace the assembly if the star wheel or threads are damaged, or the components are severely rusted or corroded. See Fig 1.

Discard the brake springs (4) and retainer components if worn, distorted or collapsed. Also replace the springs if a brake drag condition had occurred. Overheating will distort and weaken the springs.

Inspect the brake shoe contact pads on the support plate (1), replace the support plate (1) if any of the pads are worn or rusted through. Also replace the plate if it is bent or distorted. See Fig 1.