This is why the brake caliper is not releasing

In today’s traffic conditions, a brake system failure is extremely dangerous. This is especially true if the brake caliper is not releasing, pressing the brake pad into the disc. Generally, this is caused by the hydraulic piston failing to return.

You can notice this aspect when, during braking, your car is pulled to one side, and to stop you need a greater distance than usual.

Other signs include pressing the brake pedal with greater force than usual, feeling the smell of smoke after braking, and reaching the desired speed slower than before.

If that’s the case then your brake caliper may be failing because it’s not releasing and you need to fix this as soon as possible.


As part of the disc braking system, the caliper is essential. During braking, it attaches and fixes the brake pads, ensuring their mobility. A brake caliper can be either floating or fixed at the moment.

Floating calipers usually consist of at least one piston, sometimes two, located on the same side of the brake disc. A screw holds the steering joint to the support, and the support in turn is attached to the caliper housing. Brake pads are mounted on the caliper bracket.

The fixed caliper has pistons on both sides and doesn’t move when you hit the brakes. Instead, pistons on both sides move against the rotor.

For more information, check your owner’s manual. This can help you not only identify your caliper type but other parts as well. If you don’t have this guide, you can check your dealer, they are not that expensive. 

Special springs are used to mount brake pads in guide grooves properly. Whenever the brake pedal is pressed, the piston leaves the cylinder and engages the inner brake pad. Following that, the caliper bracket moves along the guide pins to tighten the outer brake pad on the disc.

The pistons are located on both sides of the brake disc in calipers with fixed construction, and there are no guide pins. As a result, when braking, the liquid under pressure is sent to both the inner and outer plates simultaneously, causing them to move. Spacer springs keep the plates from touching.

Why is the brake caliper not releasing?

The most common cause of a brake caliper that is not releasing is its seizing or sticking. A sticking brake caliper can be caused by dirt or other substances, wrong brake fluid, poor brake pads installation, worn caliper, and bent brake discs.

We will cover all these reasons below.

Exposure to moisture and dirt

Pistons and guide pins cannot move freely due to dirt accumulation. Moisture leads to corrosion which jams the caliper. In the case of a damaged rubber sleeve, which is designed to protect the moving parts from the aggressive environment, it increases the likelihood of piston and pin failure.

Moreover, locking can be caused by a brake fluid that has not been changed in time, which eventually accumulates water, corroding the piston and pin.  

Using a poor lubricant or not using any at all

To lubricate the guide pins, a high-temperature-resistant grease must be used. Unreliable grease dries out or leaks, causing damage to the rubber parts. In an inflated sleeve, the guide pin cannot move freely.

Brake discs are bent

Sudden temperature changes will cause the brake discs to bend, which in turn will cause the brake pads to stick.

Worn caliper

A worn casing, as well as a piston surface, can cause a caliper to tilt or stick. The dirt accumulated in the wear areas obstructs the free movement of the moving parts. Corrosion is accelerated by air penetration.

Worn brake pads and discs

Among other problems, using discs and pads that are too worn can cause the caliper to stick.

Brake pads are installed wrong

If you recently changed the brake pads and you experience sticking symptoms, then your brake pads were installed wrong and you need to recheck them.

Using an inadequate brake fluid

The pistons will not return to their original position if the fluid is too viscous. Furthermore, pistons made of polymeric or composite materials may swell when exposed to the wrong brake fluid.

Exposure to strong chemicals

The substances on the road and the braking fluid affect the early wear of the rubber sleeves, which is why the system must be kept tight.

Symptoms of the caliper that is ticky or not releasing

  • Greasy patches on the exterior or inside of the rim, indicating a DOT fluid leak and a drop in the expansion tank’s level;
  • Sudden, spontaneous sideways movement of the automobile after braking – when the tires are properly filled and the suspension is in good working order;
  • The principal sign of a scenario where the piston is forced in and does not return to its normal position is rattling after releasing the brake pedal.
  • The discs become extremely hot and emit a horrible burning odor, even if the braking was not done suddenly or strongly.

How to prevent the brake caliper from not releasing or sticking?

Clean the caliper when replacing brake pads

When you change the brake pads or every 5-6 months, clean the braking system components and inspect the condition of the seals. Replace any damaged seals right away.

Avoid replacing the brake fluid too rarely

Water is known to build in the brake fluid’s composition over time. This has an impact on braking efficiency and determines piston internal corrosion.

Avoid aggressive driving style

When driving on a road with a lot of turns, frequent brake pedal pressure becomes inevitable. But under normal conditions, sudden start and braking should be avoided. This will help prevent braking system elements to overheat.

Apply special high-temperature-resistant paint to the caliper to delay or prevent corrosion. Sandpaper should be used to clean and degrease the surface.

Not only will the paint protect the brake caliper from damage, but it will also offer your caliper a nicer appearance.


The brake caliper is an important car part that should that needs often attention. Its flawless operation ensures the brake system’s efficiency as well as your and your passengers’ safety.

If you ignore the earliest signs of brake caliper damage, especially if it does not release, the brakes may fail. I hope the guidelines above helped you minimize the wear and problems your brake caliper may encounter.

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