Caliper Piston Won’t Compress: Common Causes & Solutions

Car owners might come across the issue of ‘caliper piston won’t compress’ in their vehicles. They may perhaps notice that their vehicle draws more to one direction when braking or the brakes are not releasing completely after they let go off the pedal.

Such situations should be fixed straight away so that it does not affect the safety of your vehicle. To help you fix out the caliper piston problem, here are some potential causes and reasons given below.

Causes of “Caliper Piston won’t Compress”

There are many potential reasons responsible for the problem of not compressing the caliper piston. Before taking your vehicle to an auto repair shop, let’s explore out some possible causes for such problems.

1. Wear and Tear of Caliper Bolts

Why caliper piston won't compress
Solution to caliper piston won’t compress issues. Source: Youtube 

The caliper bolts comprise of slides on them that require being lubed. The shielding rubber boots present on them helps to keep the lubrication in. But, sometimes these boots get tear away by the hasty mechanics when they are mounting new brake pads. As a result, the caliper piston fails to compress.

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2. Sticky Pistons

When the brakes are applied, the brake piston seal is deformed slightly. When the car drivers let the brakes off, they uncoil and help to compress the pistons for drag-free running. If the piston fails to slide adequately on the seals, then the seal impedes the piston from permanently compressing.

3. Inactivity of the Vehicle

One of the main causes of the not compressing caliper piston is the inactivity. If you are not using your vehicle for months, it may happen that the piston gets rusted. As a result, the corrosion that is built on the caliper prevents it to compress fully, stopping your vehicle from running smoothly.

Fixing the Caliper Piston Compression Problem

Why caliper piston won't compress in your vehicle
Fixing caliper piston won’t compress problems. Source: Youtube 

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There is a need to carefully diagnose and fix such issues right away as it may put your vehicle in danger. One of the main ways to compress your caliper piston fully is to take care of the brakes. If you top-up the brake fluid and replace the brake pads when required, then you might not run into any problems with the caliper piston.

For a detained caliper piston, a special tool exists that helps to apply force and compress the pad. You can use a simple C-clamp to fix this problem. To see how to use a C-clamp to repair such problem, you can read on some car maintenance tips over the web. In addition, you should also clean the piston properly and apply a light coating of grease to compress the caliper successfully.


So, now you might be aware of the possible causes and ways to fix the caliper piston not compressing problem. In case, you think that the problem is quite hard to handle, don’t forget to seek the help of an auto professional. These certified mechanics will provide the best solution to your ‘caliper piston won’t compress’ problem.