Drum Brake System: Testing and Inspection

REAR BRAKE





INSPECTION





1. CHECK BRAKE DRUM INSIDE DIAMETER
a) Using a drum gauge or equivalent, measure the inside diameter of the drum.
Standard diameter: 200.0 mm (7.874 inch)
Maximum diameter: 201.0 mm (7.913 inch)
If the inside diameter of the drum is greater than the maximum, replace the drum.





2. CHECK BRAKE SHOE LINING THICKNESS
a) Using a ruler, measure the thickness of the shoe lining.
Standard thickness: 4.0 mm (0.157 inch)
Minimum thickness: 1.0 mm (0.039 inch)
If the lining thickness is equal to or less than the minimum, or if severe or uneven wear is present, replace the brake shoe.

HINT: If any of the brake shoes have to be replaced, replace all of the shoes in order to maintain even braking.





3. CHECK BRAKE DRUM AND BRAKE SHOE LINING FOR PROPER CONTACT
a) Apply chalk to the inside surface of the drum. Then grind the brake shoe lining on the drum until full contact is achieved.

HINT: If the drum and brake shoe lining do not have full contact, use a brake shoe grinder or replace the brake shoe.

b) After the inspection, wipe chalk off of the inside surface of the drum and lining surface.
4. CHECK REAR WHEEL BRAKE CYLINDER
a) Check the cylinder bore and piston for rust or scoring.
If necessary, replace the cylinder and piston.