Every vehicle has them, and at every wheel. A car’s brakes are the primary safety system for not just the occupants, but for everyone else around the car also. Your car’s braking system has to work reliably – and I mean every single time – you press the brake pedal, or you could be putting someone’s life in danger.
Going to a service shop or a dealership to take care of worn-out brakes is expensive. And anyone who has a relatively well-stocked supply of tools in the garage can change a set of brakes in a couple of hours. Here’s what you’ll need to replace the brakes on a vehicle, including the different designs and their main components.
How Drum Brakes Work
When you press the brake pedal, a rod extends into the brake master cylinder, forcing fluid through the brake lines toward the wheels using hydraulic pressure. At the wheel, brake fluid enters a wheel cylinder and extends pistons on either side.
The wheel cylinder sits between the ends of two crescent-shaped brake shoes. The other ends are connected at a pivot point on the other side. When the pistons in the wheel cylinder extend, it forces the shoes to extend out.
Friction material on the brake shoes then presses against the inner surface of a drum. The friction between the two parts is what causes your car to slow down and stop. In a normal brake job on drum brakes, the brake shoes wear out and are the common components to replace. While the brake drums can be resurfaced at a brake shop, it’s often simpler just to replace worn drums at the same time.
How to Change Brake Shoes and Drums
When you look at a drum brake design, it’s rather rudimentary. Still, replacing brake shoes is critical work and doing it right will help keep you safe.
What You’ll Need
- A set of new brake shoes that services a complete axle, or two wheels
- Two brake drums, possibly
- Brake cleaner spray
- Lint-free rag
- Floor jack and stands
- Hold-down spring remover
- Lug nut wrench
- Flat screwdriver
How It’s Done
Step 1: Secure your car. Put the transmission in park if it’s an automatic or engage the gearshift in gear if it’s manual. Then engage the parking brake.
Step 2: Remove a wheel. Lift one wheel off the ground using your floor jack and rest the car securely on a jack stand. Then remove the wheel using a lug nut wrench. If you have impact tools, that’s much easier.
Step 3: Loosen the adjuster. Pop the rubber plug out from the backing plate and loosen the brake adjuster using a flat screwdriver. Friction from shoes against the drum could make it impossible to remove the drum if it’s not loosened first.
Step 4: Remove the drum. It may simply slide off the wheel studs if it isn’t too rusted or seized. For most cars, a few sharp hits with a hammer on the drum face will loosen it up. Don’t hit the rounded edge or it could warp the drum!
Step 5: Remove the brake shoes. Hold-down springs need to be compressed, rotated to line up, and taken off the hold-down pins to release the shoes. Take note of the orientation for the springs and the adjuster. Better yet, take a picture. Spray down the brakes with brake cleaner and wipe down with a clean cloth.
Step 6: Install new brake shoes. Put all the parts back in place exactly as they were removed, then slide the drum over top.
Step 7: Adjust the brake tension through the backing plate. The drum should contact the shoes lightly but the drum should still be able to turn by hand.
Step 8: Re-install the wheel and lower the car. Repeat on the other side, then test drive the car to ensure the brakes are functioning correctly. Adjusting the brakes looser if the brakes are touchy, or tighter if the pedal travels too far, may be required.
How Disc Brakes Work
Disc brakes, on the other hand, appear to be a more complex design. Like disc brakes, fluid is pushed through the lines toward the wheels. The fluid enters a brake caliper mounted at each wheel and forces a piston to extend. The caliper has two brake pads with friction material mounted in it facing each other with the piston forcing one pad toward the other.
A brake disc or rotor spins between the two brake pads. As the piston extends, the brake pads squeeze against the disc. The friction causes your car to stop. Replacing disc brakes is usually as easy as installing new brake pads, although the rotor may need to be changed if it’s rusted, warped, or gouged.
How to Change Brake Pads and Rotors
Don’t be intimidated with how disc brakes look. It’s relatively simple to change the brake pads and rotors.
What You’ll Need
- New brake pads
- New brake rotors, if required
- Anti-seize compound
- Ratchet and socket set
- Pry bar
- Lug nut wrench
- Caliper piston tool
- Floor jack and jack stands
- Tie-down strap
Step 1: Secure your car. Same as with drum brakes, put the transmission in park if it’s an automatic or engage the gearshift in gear if it’s manual. Then engage the parking brake.
Step 2: Remove the wheel. Lift one wheel off the ground with the floor jack, secure it with a jack stand underneath, and remove the wheel with the lug nut wrench.
Step 3: Remove the brake caliper bracket, if equipped. Some vehicles have a bracket for the caliper that holds the brake pads, rather than requiring the complete caliper to be removed. Remove the two bolts holding the bracket and gently pry the pads and bracket off. If you’re only changing brake pads, you may be able to simply install them in the bracket, reinstall it, and put the wheel back on.
Step 4: Remove the caliper. Unbolt the caliper from the wheel knuckle. It might need to be pried and wiggled off the brake disc. Don’t let it hang from the brake hose – rather, use a tie-down strap to keep it out of the way without any tension on the hose. Squeeze the piston back into the caliper with the clamp-like tool.
Step 5: Change the brake pads. Pry the brake pads out of the caliper and install new ones. If the brake pads included a hardware kit, install the new spring-metal hardware. Lubricate the slider pins with an anti-seize compound.
Step 6: Replace the brake rotor if necessary. It should just slide off but if there are retainer clips on the wheel studs, they can be cut off with side-cutters. Clean the surface of the new brake rotor with brake cleaner and wipe it dry to remove the oil coating, then slide it into place.
Step 7: Re-install all the parts you removed in reverse order. This is straightforward and shouldn’t present challenges.
Step 8: Finish up. Install the wheel, lower the car, and press the brake pedal to extend the brake caliper piston BEFORE attempting to drive. The pedal may go to the floor initially, but then it will ‘pump up’. Test drive cautiously at first.