A brake drum is a heavy, cast-iron brake system part that looks like shallow, several centimetres-high cylinders about 23 to 30 cm in diameter. The brake drum has a precisely machined surface all around the interior circumference, that the brake shoes make contact with when you apply the brakes, transmitting hydraulic pressure through the wheel cylinder. This forces the brake shoes outward against the interior of the brake drum, resulting in friction that causes the car to slow. The brake drum is mounted over, and fully encloses, all of the rear brake components such as the wheel cylinder, springs and clips, brake shoes, and parking brake mechanism. The drum is commonly held to the wheel hub by the wheel and the lug nuts, but some configurations combine the drum with the wheel hub as one unit. Nowadays, a drum brake type system is only installed on the rear axle, if used at all, as 4 wheel disc type systems have become more common.
There are two options when it comes to brake drum service: outright replacement or resurfacing. In some cases, it is cheaper to replace the drum rather than refurbish it. In both cases though, the removal and installation procedure for the drum is the same.
No. Should there be a deficiency with the brake drums, stopping distances will not be as short as possible. In a panic stop, stopping just five or ten feet shorter could be the difference between no collision and a collision. Any deficiency in a vehicle’s braking system is a cause for concern and a potential safety issue. Have the brake drums inspected at your earliest convenience to determine if a problem exists and find out what must be done to fix it.