Measuring the thickness of the brake shoe linings of the rear drum brakes (Fiesta 4)

The lining on the advancing brake shoe is always thicker than on the releasing brake shoe: during operation, the advancing brake shoe wears out faster, so both linings reach the wear limit at about the same time, which should not exceed 2.5 mm, including the base of the brake shoe. Thinner shoes are replaced in pairs on both sides of one axle of the car. To check the thickness of the brake shoes on the rear axle, both brake drums must be removed. Measure the inner diameter of the brake drums with a 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.