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What Are the Signs of a Frozen Brake Caliper?

Close-up of a brake caliper

Brake calipers are a central component of your braking system and not something to ignore if you’re experiencing problems. One issue that can pop up is a frozen brake caliper, and since the results are potentially dangerous, you’ll want to know the signs.

Brake DanceFrozen Brake Caliper

Calipers are mounted on disc brakes, so each rotor is sandwiched between two brake pads. When the driver applies pressure to the brake, brake fluid is sent to pistons inside the calipers, forcing them together and applying pressure to the pads, so they squeeze the rotor until it, and the vehicle, stops. A frozen caliper can show up for many different reasons, but it results in the piston not moving in and out as smoothly or completely as it should. This causes all sorts of long- and short-term problems and, most importantly, impacts your ability to brake. Be on the lookout for the following signs to catch problems as they appear.

Listen Up!

Do you hear a noise every time you apply the brakes? Even if it isn’t a frozen caliper, you need to look into it ASAP. If it is a caliper, you might hear a grinding or high-pitched squealing as the metal rotor drags through the brake pads.

If You Can’t Take the Heat…

All that metal-on-brake-pad friction causes a lot of heat very quickly, which can potentially warp and break components or melt parts like the rubber brake lines. And once your brake lines are destroyed, you have no service brakes at all.

Warning: Do not touch calipers with your bare hands to try and discern how hot they are. If seized, they can be very hot after driving even short distances.

What’s That Smell?

Burning rubber, perhaps? The unpleasant smell of hot brake pad friction material is a good indication that something is wrong.

Leaking Fluids

A frozen brake caliper can cause leaks by damaging hoses or can leak internally in the caliper itself, such as in the boot around the piston. If the boot is brittle from heat exposure and/or ridden over rusty piston surfaces, it can release fluid.

Such a Drag

“Brake drag” refers to a situation where the pads drag along the rotor, causing you to feel like your brakes are still holding while you drive. Depending on how much pressure the caliper is exerting on them, they may slow your vehicle, cause rough braking or render the car undrivable.

Please Stop

Conversely, if there’s a leak or if the pistons are seized in a position further away from the rotors, they may not put any pressure on them at all when you need to stop or slow down.


Lastly, if a caliper is frozen, you might notice your car pulling in the direction of the binding caliper while driving. Note this could also be an alignment issue, so check for other signs to confirm the issue before changing any calipers.

Driving with a frozen caliper is dangerous business, and usually the best option is to replace it. Just remember that calipers should be replaced in pairs because if one goes, the other probably isn’t far behind.

Check out all the calipers available on NAPA Online or trust one of our 17,000 NAPA AutoCare locations for routine maintenance and repairs. For more information on brake calipers, chat with a knowledgeable expert at your local NAPA AUTO PARTS store.

Photos courtesy of Blair Lampe.


Blair Lampe View All

Blair Lampe is a New York-based professional mechanic, blogger, theater technician, and speechwriter.  In her downtime she enjoys backpacking wherever her boots will carry her, rock climbing, experimental theatre, a crisp rosé , and showering love on her 2001 Sierra truck.

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