Braking Problems? How to Tell if It's a Stuck Brake Caliper

March 8, 2018

Your brakes can act funny in a number of ways. They might squeal or grind, they can pulse or feel soft — they might even drag your car to one side. If you notice that last one, there’s a chance you have a stuck brake caliper. It’s not a common issue, but like all brake problems, you’ll want to get it inspected immediately.

How brake calipers work

There are two types of brakes: disc and drum. If you are driving something less than 25 or 30 years old, you most likely have disc brakes. 

Disc brake systems use calipers, pistons, brake pads and rotors to ensure that you stop when you need to. When you press the brake pedal, pressurized brake fluid is sent from the master cylinder to the calipers, forcing them to clamp your brake pads down on the rotor. Picture yourself spinning a CD on one finger and using two fingers from your other hand to make it stop. Your rotor is the CD and your fingers are acting like the pads and calipers.

To make things more confusing, there are also two types of caliper systems: fixed and floating. Fixed calipers are exactly that. The calipers are mounted in one spot and use pistons to clamp your brake pads down. The pistons in a fixed caliper system compress on both sides of your rotor.

Floating calipers use a more complicated system in which the calipers, pistons and brake pads are all housed in one unit, with the pistons on the inner side of your wheel. They work by moving the brake pad and then pushing the caliper away from the rotor. This in turn causes the brake pad on the outer side of your wheel to engage with the rotor and stop your car.  

Get it diagnosed by a professional

Signs you have a bad brake caliper

A bad caliper can wear down your brakes and make it hard to stop, so get it checked out right away. The most common signs of failure for brake calipers are as follows:

It feels like the brakes are always on: If the caliper is stuck in a way that doesn’t let the brake pads fully release, it will feel like your car isn’t going as fast as it should, or like the parking brake is on. 

Your car pulls to one side: This can happen when braking or when just driving. Typically, pulling to the right or left is a sign that you need a wheel alignment, but it can also mean you have a stuck caliper piston.

Brake fluid leak: Wear and tear or a faulty piston can cause a brake fluid leak. This usually is caused by breakdown of protective rubber seals that let this mechanism to move, and can happen in both fixed and floating caliper systems. You might also smell burning rubber.

Reduced braking power: This can be another sign of a brake fluid leak. If your car is low on brake fluid, you may feel little or no response when you press the brake pedal. Another possibility is that your caliper sliders are stuck. If they get dirty or gummed up, it can hinder their ability to clamp down. This is fairly common in floating caliper systems and will be feel like your brakes are spongy — like it takes extra effort to make the vehicle stop.

Brakes make odd sounds: Despite the temptation to crank your radio up to drown out the sound of your brakes grinding, it’s much wiser to take care of the problem. When you have caliper issues, the brakes may be very loud when you try to stop. It can be a high-pitched screech, a thud or a metal-on-metal grinding noise. These sounds can mean that your caliper is stuck, that it has come loose or that it’s having some other problem. 

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Brake caliper repair advice

If you suspect that you have a braking problem, have your mechanic inspect your car. If you have a leaking caliper, it’ll likely need to be replaced — very few shops will try to repair a leaky brake caliper. 

If you have a fluid leak, the part that’s causing the problem will likely need to be replaced. If your caliper slider is gummed up, you can remove the pins, clean them and reinstall them with fresh, high-temperature lubricant. A light duty metal brush can help clean the area so the mechanism is able to move without any problems.

It’s often best to have them replaced in pairs, as the other side may be close to failing, too. You may have to spring for new brake pads or other items, depending on how much damage the bad caliper has caused. We highly recommend having the brake hydraulic system flushed when replacing calipers. 

About the Author

Bluma Stock is an automotive expert at RepairPal, the leading online source of auto repair resources and estimates. With many ASE Master certified mechanics on staff who have decades of experience, RepairPal knows all the fine points of car repair.