Tip of the week
Many motorists allow their brake pads to almost completely wear out before replacing them, but this is false economy. A brake pad that is excessively worn is more likely to overheat and fade during demanding braking events like descending a mountain pass.
More seriously, the friction material on the brake might wear out completely, resulting in the metal brake pad backing coming into contact with the brake disc.
Metal-on-metal contact ruins a brake disc very rapidly and means you will have to replace not only the brake pads, but the discs too, which can treble the price of your brake replacement. Metalon-metal contact also dramatically reduces braking efficiency and can cause the car to pull to one side when braking. Rather play safe and replace the brake pads once the friction material has worn to three millimetres to maintain a good margin of error in these safety-critical items.
Tip courtesy of the Automobile Association