Question 1

When brake shoes need replacing

Accepted Answer

Brake shoes are the wear parts of drum brakes that press against the drum's inner surface during braking. Drum brakes are common at the rear of older cars — modern cars almost always have disc brakes. The shoes' friction surface is about 4–6 mm thick when new, with a minimum thickness of 1–1.5 mm.

Symptoms of worn shoes: weakening on braking, pulling to one side from the rear wheels, poor parking brake hold and possibly a metallic sound when braking (the shoe surface is worn through and the underlying metal is rubbing the drum).

Question 2

How brake shoes are replaced

Accepted Answer

The rear wheel is removed and the drum brake cover is opened. Old shoes are taken out — they have many small springs holding them in place. The drum is inspected for wear marks — if the drum is badly scored it's replaced at the same time.

New shoes are fitted with new springs. Parking brake cable action is checked and adjusted. The drum is refitted and braking effectiveness is tested on a test drive. Shoes on both rear wheels are always replaced at the same time.

Question 3

Why are drum brakes different from disc brakes?

Accepted Answer

Drum brakes' advantages are cheap manufacture and self-energising action — the shoes lock into the drum on braking and automatically add clamping force. The downside is lack of cooling — shoes and drum don't cool as effectively as an open disc system. This isn't an issue on rear wheels where braking force is lower, but it's the reason modern cars use disc brakes on all wheels.

Brake Shoe Replacement in Vantaa