How To Free A Stuck Brake Caliper Piston

180 Automotive is reader-supported. This post contains affiliate links. As an Amazon Associate I earn from qualifying purchases.

How to free a stuck brake caliper piston isn’t as difficult as it seems. Whenever you experience this, just bring out the piston from the disc while pressing the brake pedal.

This is to ensure that the brake is far from the region of corrosion or rust. Different factors may be responsible for a stuck brake caliper piston in your car, especially corrosion.

However, freeing a stuck brake caliper piston may not even require you to hire a professional. The interesting thing about this is that brakes’ hydraulic can use pressure to knock the piston off.

Step-By-Step Guide To Unstick A Brake Caliper Piston

Step-By-Step Guide To Unstick A Brake Caliper Piston

As we’ll come to know later, corrosion is the main cause of stuck brake caliper. When you have a stuck caliper piston, the solution is to find a means to unstick it from the caliper, far away from the corrosive area with the use of a specialized tool.

To free a stuck brake caliper, you should carry out a diagnosis first.

1. Inspect The Parts

The first step towards freeing the stuck caliper is to inspect the various surrounding parts to know if they’re in their correct positions. Check the caliper and piston, brake hose and line, brake master cylinder, brake fluid, brake line connector.

2. Bleed The Fluid

The next step is to bleed the brake fluid. To do this, open the bleed valve before letting out the brake fluid. You can use vacuum, pressure, or gravity to expel the fluid. After this, fill the system before you finally close the bleed valve.

3. Check The Push Rod

You also inspect the length of the pushrod. If it’s too long, the brake caliper can become frozen. In this instance, you should simply remove the rod and cut it up to size. At best, you should replace the rod with the normal pushrod meant for the vehicle.

For other general procedures, carry out the following steps:

  1. Jack Up The Vehicle: Placing your floor jack, lift the car on the jack stand. Don’t forget to park the car on a level surface and chock it.
  2. Remove The Wheel: With your lug wrench, turn the lug nuts counterclockwise. Continue to twist until the nuts are finger tight. Remove the nuts and the wheel to access the stuck brake caliper.
  3. Unbolt The Stuck Brake Caliper: With your socket set, pull up the frozen brake caliper and take it off from the caliper bracket.
  4. Clean The Caliper: After removing the caliper, you should clean it and get rid of all gunk, brake dust, lube, and rust. Ensure you use the right brake cleaner and rag. The caliper pins should also be thoroughly rid of all gunk and built-up lube.

Alternatively, in some cases, the use of a C-clamp helps to solve this problem. Also, you can just unstick the brake using a can of compressed air. As I explained earlier, the piston may miss its contact if the brakes’ hydraulic knocks it off.

By taking out the piston from the disc brake and pressing the brake pedal, everything gets back to normal since it is a car from the corrosive area.

Why Will The Brake Caliper Get Stuck?

Our first call should be to ask what’s responsible for the brake caliper piston to get stuck in the first place. A few things may cause your brake caliper piston to get stuck.

1. Corrosion

Predictably, corrosion is one of the most common reasons for your stuck brake caliper piston problem. Corrosion is often caused by a lack of lubricant. For instance, once the caliper bolts become dry without lubricant, debris and rust will build-up, causing the brake caliper itself to freeze or stick.

2. Too Long Push Rod

If the pushrod is longer than the standard length, the brake caliper may get stuck. The rod will push the master cylinder, forcing brake fluid pressure to the caliper pistons.

3. Dry Caliper Bolts

Normally, the brake caliper bolts should be periodically lubed up to keep the smooth when sliding. However, once they become dry and without adequate oil, these rubber-made bolts can cause the brake caliper to freeze. The protective rubber layer can tear and cause the lubricant to spill out

4. Brake Caliper Slides

The pads are designed to slide through the caliper grooves. But when there’s debris buildup that causes corrosion, the brake pads will fail to slide out of the grooves after taking your foot off the pedal. Eventually, the pads will freeze in the grooves.

5. Torn Piston Rubber

The rubber boot on the brake caliper piston is intended to lubricate and protect the piston. However, once the rubber tears, rust, and debris can easily find their way into the caliper. This will reduce the sliding power of the piston. Rubber can tear due to careless handling or age.

6. Worn Brake Hose

The brake hose is a very fragile part of the braking system. It can wear out over time and begin to crack, causing brake fluid to leak away onto the piston head. Once the fluid cannot return to the master cylinder, the caliper will automatically get stuck.


What Symptoms Do I Need To Watch Out For?

What Symptoms Do I Need To Watch Out For?

The braking system may drag or bind after it is stuck. However, certain symptoms are noticed before the piston can stick with the caliper. At times, the brakes feel like they’re on when you try to drive your car.

Also, car movement may be very difficult, and you may experience irresponsible braking applications. Your car may also pull to one side, among other symptoms.

Do I Need A Brake Caliper Rebuild? If Yes, Why?

Freeing a stuck brake caliper piston does not mean the problem is gone forever. Chances are, it may come back in time. You shouldn’t forget that you only provided a temporary solution by bringing out the piston from the disc brake, however, the rusty part remains, exposing the brake to stuck again.

To avoid this problem, it is best to replace the old caliper with a new one. Although this exercise will cost you a bit, it is worth it. Rebuilding the old one will also cost you a bit, therefore, why not replace it once and for all, if you are a DIY enthusiast, then you may find it an easy task.

The process can be tedious since it involves cleaning thoroughly all the components after you disassemble them.

You may consider rebuilding if the level of corrosion is not alarming. Corrosion may, however, be bad that there are no two options other than a caliper replacement. A brake hose may be the only required tool you need at times for cleaning the inside bore.

How Do I Prevent Brake Caliper Piston From Stocking?

The braking system gets a little attention, yet, we use it almost daily. There is a simple and recommended way to prevent this issue from springing up in the future- by checking the braking system regularly. Find out if any of the components have worn out. You can also find any corrosion signs.

What you should always put in mind is to ensure adequate lubrication of the braking system for its smooth running. Also, avoid using substandard or low-quality oil for the braking system.

High-quality oil will help lubricate and protect the pitons, including the sliding pins. Abandoning your car for a longer period is also a practice you must avoid. Even if it will be once, ignite it to avoid this problem.

Final Thoughts

Even while I have provided you with an answer to the question “How to free a stuck brake caliper piston”, I must still stress the importance of regular maintenance on the braking system. Always ensure to follow preventive measures to avoid a stuck or damaged brake caliper piston.

However, taking note of symptoms is a great way to catch underlying problems earlier before they become bigger. Be watchful of how your car works.