Measuring the lining thickness of the rear drum brake pads

The pad on the advancing brake pad is always thicker than on the retracted brake pad: during operation, the advancing brake pad wears faster, so both pads approximately simultaneously reach their wear limit, which should not exceed 2.5 mm, including the base of the brake pad. Smaller pads are changed in pairs on both sides of the same vehicle axle. To check the thickness of the rear axle brake pads, both brake drums must be removed. Measure the inner diameter of the brake drums with a vernier caliper: for a new drum it is 180 mm. Oval brake drums must be given to a car repair shop for boring - provided that the inner diameter does not exceed 181.5 mm.