How to Reset Disc Brake Pistons
Disc brakes are more common on modern cars than drum brakes, but there is some maintenance involved even with disc brakes. Sometimes the pistons will get stuck in the caliper and need to be reset. In this blog post, we are going to show you how to reset disc brake pistons. This process can take up to an hour or two, depending on how often this has happened before.
The first step of this process is gathering all necessary tools, including a wrench set, penetrating oil, brake cleaner spray, clean rags/towels, and safety glasses. Once these items have been gathered, it’s time to get started!
Begin by applying penetrating oil into the bleed screw hole, then wait 5-10 minutes for it to soak in a while, continuing to turn the screw clockwise until you hear air bubbles stop coming out of the piston. Read on to know more!
10 Ways on How to Reset Disc Brake Pistons:
1) Bleed your brakes.
If your brake fluid is old and dirty, it’s likely the cause of the sticking piston. And good chance fresh new brake fluid will flush out and clean and free up the stuck piston (just like flushing dirt out of a fountain pen).
2) Remove the Brake Caliper.
Removing your brake calipers will give you access to all pistons, not just one at a time. This is the most effective way to free up sticking piston issues as it allows for easy access to both sides of every piston. A crescent wrench or a socket with an extension may be necessary for tight pistons.
3) Remove the Offending Rotor/drum.
The disc brake pads are attached to the caliper by metal pins that sit in slots of the braking surface (rotor, drum). If your brakes are sticking, remove one pad so you can get access to the piston underneath. When re-installing the pad, keep some brake cleaner spray handy. If the piston is stuck, you may need to spray both sides of it with Brake Cleaner so it can move back and forth through its slot without binding.
4) Use an Anti-seize Lubricant.
If your brakes are still sticking after removing the brake pads, rotor, and caliper (or if you need to remove the pad pins), you’ll have access to check out each piston. You can then use an anti-seize lubricant to free up the pistons that are sticking. I recommend using Brake Parts plus Organic Anti Seize Lubricant.
5) Use a Penetrating Lubricant and Compressed Air.
Another way to free up sticking pistons is to use a penetrating lubricant and some compressed air. Some people take an air hose and blow it into the brake caliper, but we would suggest using an air compressor or, even better, one of those cans that hold 18 liters of compressed air, such as the Kobalt 18-Volt Lithium-Ion Dustbuster.
6) Use a Hand Drill.
Suppose you can’t get your brake pistons to move with any of the above suggestions; the only way to free up jammed brake pistons may be by using an electric or manual (battery operated) bit for a hand drill. This method is the most effective way to free up your brake pistons if you have access to one.
7) Use Heat.
Heat will help to expand the brake piston, free up whatever is causing it to stick, and allow you to remove it with ease. You can use a propane torch or an acetylene torch (if you have access to one) for this purpose. After heating, be sure your brakes are cool enough before re-installing any piston.
8) Use a Grinding Bit for an Electric Drill.
If you can’t free up your brake pistons with heat and they’re still stuck, another way to get the job done is by using a grinding bit for an electric drill. We recommend heating the piston first since it’s likely that whatever is causing the sticking problem will melt when heated and be easier to remove.
9) Drill Out Your Brake Piston.
If you’ve tried all the above suggestions and your pistons are still stuck, one way to get it unstuck is by drilling out the top of the piston. This will allow the brake fluid to escape, which will make for easier removal. You’ll need a drill with a 7/64 inch bit for this purpose. Be sure to keep the bit lubricated, so it doesn’t bind up.
10) Replace Your Brake Pistons.
Replacing your brake pistons is not always necessary, but sometimes it’s the only way to free up jammed brake pistons that cannot be removed by any other means (heat, air pressure, penetrating oil, etc.). If you find your brakes are sticking and you’ve used all of the above suggestions, but nothing is working, replacing your brake pistons is likely your next step.
Why Should You Reset Disc Brake Pistons?
If you are driving around with your vehicle’s brakes feeling less responsive than usual, or there is a grinding sound when you press down on the brake pedal, this may be due to the wear of your brake pads. When brake pads have become worn out, they can compress too much along with the rotors and cause them to squeak under braking force.
This is also where the piston reset process comes into play. If your brake pistons do not retract back to their normal position when you release the brake pedal, they may need some assistance in performing this action using the “piston-reset” tool.
Conclusion:
If you’ve got a disc brake that needs to be serviced, make sure you know how to reset disc brake pistons. The steps are simple but, if not done correctly, can cause damage and injury. On the other hand, this will help them last longer and keep the braking system in good condition. The first step is to remove all the old grease from all surfaces with kerosene or some other solvent (we use acetone).
Next, apply new lubricant; you can even use WD-40 if it’s available. Finally, wipe down all parts with an oil cloth before reassembling everything back together again. You’ll be happy that you did! If not, be sure to reach out for help or more information on our services page. You can also find helpful guides about how to fix other common auto-repair problems on our website.
Louis Wein
Louis has always been fascinated by cars. He loves the way they look, the sound of the engine, and how they make him feel when he's driving. He is always keen to learn more about different mechanics of cars and how the engine contributes to other aspects of the car. As an automotive technician with over 10 years of experience, he knew how they worked and loved taking them apart to see how they went back together. He was especially interested in the mechanics of combustion engines and loved finding ways to make them more efficient. He loves to work on cars and help people keep their vehicles running smoothly. As a senior editor, he enjoys contributing to Diy quickly because it allows him to share his knowledge and expertise with others.
