Drum Brake System: Testing and Inspection

INSPECTION





1. INSPECT BRAKE DRUM INSIDE DIAMETER
(a) Using a brake drum gauge or equivalent, measure the inside diameter of the drum.
Standard inside diameter: 228.6 mm (9.000 in.)
Maximum inside diameter: 229.6 mm (9.039 in.)





2. INSPECT REAR DRUM BRAKE SHOE LINING THICKNESS
(a) Using a ruler, measure the thickness of the shoe lining.
Standard thickness: 5.5 mm (0.217 in.)
Minimum thickness: 1.0 mm (0.039 in.)
If the lining thickness is at the minimum thickness or less, or if there is severe, uneven wear, replace the brake shoe.





3. INSPECT BRAKE DRUM AND REAR DRUM BRAKE SHOE LINING FOR PROPER CONTACT
(a) Apply chalk to the inside surface of the drum, then grind drum on the brake shoe lining to fit.
If the contact between the drum and the shoe lining is improper, repair it using a brake shoe grinder or replace the brake shoe assembly.
4. INSPECT BRAKE WHEEL CYLINDER
(a) Check the cylinder bore and piston for rust or scoring.