Use Rotunda Brake and Clutch Service Vacuum 091-00001 or equivalent to
remove all dust from backing plates and interior of brake drums.
Inspect brake shoes for excessive lining wear or shoe damage. If lining is
damaged or worn within 0.8mm (1/32 inch) of the rivet heads on riveted linings
or 1.5mm (1/16 inch) of the shoe on bonded linings, it must be replaced.
Replace any lining that has been contaminated with oil, grease, or brake fluid.
Replace lining in axle sets only. Never replace just one shoe of a brake
assembly. Replace both leading and trailing shoes. Prior to replacement of
lining, drum diameter should be checked to determine that brake drum diameter
is within specification. If braking surface diameter exceeds specification,
drum must be replaced.
Check condition of brake shoes, retracting spring, hold-down springs, and
drum for signs of overheating. If shoes have a slight blue coloring, indicating
overheating, retracting and hold-down springs should be replaced. Overheated
springs lose their tension and could allow new lining to drag and wear
prematurely, if not replaced.
Inspect all other brake parts and replace any that are worn or damaged.
Inspect brake drum and, if necessary, refinish. The maximum inside diameter
is shown on each brake drum. If maximum inside diameter is exceeded either by
wear or refinishing, drum must be replaced.