Your vehicle’s braking system is the most common and arguably most important safety feature of your car or truck, and a proper working brake system is imperative to safe operation. Proper maintenance and repair of your brakes is imperative of course, and – in our opinion – the last place you would want to cut corners.
A drum brake system is typically found on the rear wheels on older passenger cars and light trucks. A couple decades ago, they were in wide use for both the front and rear. They call it a “drum” brake because the parts you see above are inclosed inside a “drum” which surrounds the shoes, wheel cylinders and hardware. When the brake pedal is depressed, hydraulic fluid from the master cylinder is pushed out and down to the wheel cylinders. The wheel cylinders push the shoes out and contact the inside of the drums and provide friction to slow and stop the vehicle. When the pedal is released, the fluid pressure is reduced and the springs and hardware are responsible for pulling the shoes back to their neutral position.
When performing service on rear brakes, shoes will be replaced and drums will be machined if possible. If the drums are too thin to be machined, have hot spots, or vibration is felt from the rear wheels, drums would likely need to be replaced. If the shoe hardware is rusted or otherwise weak, replacement hardware should be installed. Lastly, the wheel cylinders should be inspected – if there is evidence of fluid leaking through the wheel cylinder seals, then the cylinders should also be replaced. When the system is serviced, the drum brake system is cleaned and adjusted to make sure the shoes are in the correct position.
Disc brakes are so named because a disc is used as the medium to apply friction and stop the vehicle. This is the latest and most efficient braking system used in today vehicles, and you usually find them in the front and rear of the vehicle.
In this system, a pad holder suspends the pads on either side of the brake rotor. When you depress the brake pedal, hydraulic fluid is pushed through one or more pistons inside of a brake caliper. Those pistons cause the caliper to squeeze the brake pads onto the brake rotors providing the friction necessary to stop the vehicle.
When repairing a disc brake system, some considerations need to be made. One of the main issues is whether or not to replace the rotors when replacing brake pads. Years ago, brake pad material was very soft. Additionally, brake disk material was very hard and the disks had a lot of “meat” on them meaning it was possible to machine the rotors during brake jobs maybe two or three times throughout the life of the rotor.
As time has marched on, the composition of brake pads has changed – from Asbestos and other organic materials to ever harder materials – first Semi-Metallic, Metallic, and now Ceramic materials. Brake rotors have become lighter and thinner to cut down on weight, which helps improve the fuel economy of today’s vehicles. Additionally, the harder brake pads tend to wear into the brake rotors over the life of the pads, making an already thin rotor even thinner. Most brake rotors become too thin to machine, or if they are machined, they tend to warp and create a pulsation when applying the brakes.
Based on years of experience performing brake work on late model vehicles, we have found that replacing the brake pads AND rotors during a brake job provides better stopping power and quieter operation than replacing pads on old rotors, or trying to machine old rotors. We also inspect, free up and lube the calipers and slides to make sure a caliper will not hang up due to a lack of lubrication.
Lastly, it is also important that brake fluid be flushed every 2 years at the time of a brake job. Brake fluid tends to absorb moisture over time, and changing out the brake fluid in 24 month intervals is vital to the internal health of your brake system. Nearly all vehicle manufacturers recommend brake fluid flushes at 24 months.