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 in the last 25 years as a head 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 that the brake rotors are warped. Excessive side-to-side runout causes the car to shake, especially when coming to a quick stop from highway speed. Rotors can be machined or coated to make them look like the real thing again, as long as they are thick enough. If there is no brake pulsation or jerk, the brake pads can be replaced without machining. However, in my experience, if you don’t machine or replace the rotors when doing brake work, most of the time there will be excessive squeal after a very short time. I recommend taking care of the rotors by machining or replacing them when you do the brake work.
Raise 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 somehow fails while someone is working under the car? I cannot stress enough the importance of having the car safely jacked up in place, in case the car falls over for any reason. An undercar jack stand is very important for any job that takes place under the car, such as oil changes, starter motor replacement, or any other job that could crush a person if the jack fails. I once worked with a mechanic who was changing his starter motor at home. His hydraulic jack had a slow leak and before he realized the car was gradually descending on him, he was pinned under the car and was unable to get out from under it. His chest compression only allowed her to take very shallow breaths, limiting his ability to yell for help! Fortunately, a friend stopped, saw what was happening, and pulled the car up for him. If he wasn’t lucky, 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. Typically there will be two bolts holding the caliper and two bolts holding the caliper mount. Usually the caliper can 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 on older style setups, they will be held in place by the wheel bearings. Most Today’s cars will have rotors that slip. The wheel bearings in this design are non-serviceable, meaning they are greased for life and can only be replaced when they fail so they don’t get re-greased during a brake job like in the past.
pushing the piston
The brake caliper piston needs to be pushed in again 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 calipers can be used to compress the piston back into the caliper. There are also brake tools that can be used to push the piston in. A big C-clamp used to be my favorite method of getting the piston back into the caliper. If you’re working on rear disc brakes, a piston push-back tool like the KD 41540 (one of DenLors’ best sellers) is usually required to push in and re-seat the pistons. It is recommended to open the brake bleeder screw when pushing the piston, this allows it to re-enter more easily and prevents damage to the master cylinder and/or ABS (Anti-Lock Brakes) pump/valves from forcing fluid back old to the system . Closing the bleeder valve immediately after pushing in the caliper piston 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 slips on some caliper brackets that can freeze up or 16 as well that can cause uneven pad wear. The sliders should be removed and lubricated with silicone gel or disc brake grease. The sliders must work freely for the brakes to work properly.
Installing the 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 towards the rotor. My uncle a long time ago, before I started working on cars, he did a brake job on his Cadillac. I remember hearing that he put the brake pads in backwards! He ruined 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 have plastic to peel off before installing, others may have built-in tabs. Please note that if supplied, the OE (original equipment) pad insulators will not be reused. Once the pads are in place, be careful not to KIND the brake caliper hoses when reattaching the calipers. It is a common mistake to twist them and the hoses can twist in turns.
Pump the brake pedal!
After everything is back together, it’s time for a test drive. But first step on the brake pedal before you start the car! The pedal will go to the floor and you may crash if you don’t. When the pedal is pumped, the pistons are pushed and the pedal becomes firm. There was an auto technician I worked with who forgot to pump the brakes after doing brake work. He backed out of his service bay, when he braked the car kept going and crashed into the car 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 who has hands-on experience to guide you through your first brake job.
