DIY Brake Pad Replacement – How to Change Pads and Avoid Common Mistakes

Doing your own brake work, if done correctly, can save you a lot of money. But if a brake job is done incorrectly, it could cost more than paying a professional to do the job. I have done hundreds of brake jobs over the last 25 years as a master auto technician and in this article I will outline some of the basics. I also point out some common mistakes beginners and even professionals can make when doing brake work.

pulsating?

If the car shakes when the brakes are applied, this means the brake rotors are warped. Excessive side-to-side runout causes the car to shake, especially when coming to a quick stop from freeway speed. The rotors can be machined or coated to make them authentic again, as long as they are thick enough. If there is no pulsation or brake jerk, the brake pads can be replaced without machining. However, in my experience, if you don’t machine or replace the rotors when doing a brake job, more often than not there will be excessive squealing after a very short time. I recommend taking care of the rotors by having them machined or replaced when you do the brake work.

Lift the car safely

Sounds a bit too basic, doesn’t it? I have seen many people under cars without having a jack stand in place for safety. Hydraulic jacks are great, but what if one slips or fails in some way while someone is working under the car? I cannot stress enough the importance of having the car safely raised with a jack in place, in case the car falls over for any reason. An under car jack stand is very important for any work that is done under the car, such as oil changes, starter motor replacement, or any other work that could crush a person if the jack fails. I once worked with a mechanic who was changing his starter at home. His jack had a slow leak and before he realized the car was gradually descending on him, he was trapped under the car and was unable to get out. The compression of his chest only allowed him to take very shallow breaths, limiting his ability to cry out for help! Fortunately, a friend stopped, saw what was happening, and got in the car for him. If it wasn’t for luck, this could have had a totally different outcome, his mistake could have cost him his life.

Removal of wheels, calipers and rotors

After removing the wheels, locate the caliper bolts and check what type of head the bolts have to determine what tools will be needed. Common fasteners will have regular, allen, or torx bolt heads. Usually there will be two bolts holding the caliper and two bolts holding the caliper bracket. The caliper can usually only be removed if only the brake pads are replaced. Suspend the caliper with a bungee cord or something similar to prevent the weight of the caliper from damaging the brake hose. If the rotor is removed for machining or replacement most of the time, the caliper bracket will also need to be removed. The rotors will simply slip on or, in older style setups, be held in place by the wheel bearings. The majority today’s cars will have rotors that slip. The wheel bearings on this design are non-serviceable, meaning they are greased for life and can only be replaced when they fail so they are not re-greased during a brake job like in the past.

pushing the piston

It is necessary to re-push the caliper piston to install the new brake pads. The piston slowly extends as the brake pads wear. This is why it is not necessary to adjust the brakes for the disc brake system, it is basically self-adjusting. Large channel locking pliers can be used to compress the piston back into the caliper. There are also brake tools that can be used to push the piston back in. A big C-clamp used to be my favorite method of getting the piston back into the caliper. If working on rear disc brakes, a piston backing tool like the KD 41540 (a DenLors best seller) is usually required to push and re-seat the pistons. It is recommended to open the brake bleeder screw when pushing the piston, this allows it to go back in more easily and avoids possible damage to the master cylinder and/or the ABS (anti-lock brakes) pump or valves that force the old fluid back into the brake system. system. . Closing the bleeder valve immediately after the caliper piston is pushed in will ensure that the brakes do not need to be bled. If the caliper boots are broken, the caliper needs to be replaced. Broken boots will allow moisture and dirt to enter the surrounding area of ​​the piston and cause it to stick or sixteen. There are slippages in some caliper mounts that can freeze or sixteen as well that can cause uneven pad wear. The sliders must be disassembled and lubricated with silicone gel or disc brake grease. The sliders must work freely for the brakes to work properly.

Installation of brake pads and calipers

Take note of any possible differences between the left side brake pads and the right side brake pads. There are also sometimes differences in the inner and outer brake pads. Obviously the friction part of the brake pad goes to the rotor. My uncle a long time ago, before I started working on cars, he did some brake work on his Cadillac. I remember hearing that he put the brake pads in backwards! He blew out the brake rotors on him. It seems like an impossible mistake, but when you’re not familiar with what you’re doing, anything is possible. With aftermarket brake pads, most of the time they will come with their own noise isolators that fit into the back of the pads. Some will have adhesive backs that will have plastic to peel off before installing, others may have built-in tabs. Please note that if supplied, OE (Original Equipment) pad insulators will not be reused. Once the pads are in place, be careful not to TWIST the caliper hoses when refitting the calipers. It is a common mistake to twist them and the hoses can twist at the turns.

Pump the brake pedal!

After everything is back together, it’s time to take a test drive. But first step on the brake pedal before putting the car in gear! The pedal will go to the floor and you may crash if you don’t. When the pedal is pumped, the pistons push and the pedal becomes firm. There was an auto technician I worked with who forgot to pump the brakes after doing some brake work. He backed out of his service bay, when he braked, the car kept going and collided with the car that was halfway up the rack behind him. He broke the rear window of the car he was driving, luckily there was no other damage.

There are many types of brake systems, but most disc brakes are basically the same. Following the steps I’ve listed here should help replace your brake pads. But if you’re not entirely sure, it’s always a good idea to ask a friend with hands-on experience to guide you through your first brake job.