If you’re like me—and almost everyone else on the planet—you rarely think about your brake calipers. While brake pads must be replaced periodically, calipers should last the life of the vehicle. But that doesn’t always happen.
A friend of mine recently had a bad brake caliper take her by surprise. Her Honda had suffered from a low and soft brake pedal, but because some other work had been previously done on the vehicle, she was convinced the problem was due to improper bleeding after repair.
After attempting to bleed the brakes several times, and replacing the master cylinder, she decided to call me.
When I arrived on the scene, we quickly traced the problem to a faulty left front brake caliper. And so the bad caliper was replaced, normal braking ability resumed, and all was well again.
What are the Symptoms of a Bad Brake Caliper?
Think you might have a bad brake caliper on your hands? If your car is exhibiting one or more of the following symptoms, you may be right.
Here’s how you can tell if your brake caliper has gone bad:
Pulling to one side
A seized brake caliper or caliper sliders can cause the vehicle to pull to one side or the other while braking. Sometimes the car will pull while driving down the road as well.
Brake calipers, which are activated by hydraulic fluid, can develop brake fluid leaks from the piston seal or bleeder screw.
Spongy or soft brake pedal
A caliper that is leaking can cause a spongy or soft brake pedal. Also, a seized piston or sticking sliders can create excessive clearance between the pad and rotor, causing abnormal pedal feel.
Reduced braking ability
Obviously, if you’ve got a faulty caliper, resulting in a soft brake pedal, your car will exhibit reduced braking ability.
Uneven brake pad wear
Uneven brake pad wear is often caused by sticking caliper slider pins. In some cases, a sticking caliper piston can also cause uneven wear. The reason being, in both scenarios, the pads will be partially applied, causing them to drag across the rotor.
A stuck brake caliper can cause the pads to be pressed against the rotor while driving. As a result, the car may exhibit a dragging sensation, since the brakes at the affected wheel are applied (or partially applied) at all times.
Eventually, a sticking brake caliper will wear down the brake pads. And when that happens, you’ll hear the familiar sound of grinding brakes.
What to Do if You Think You Have a Bad Brake Caliper
Don’t gamble with your brakes. Period. A seized or sticking brake caliper can lead to partial or complete loss of braking ability. If your vehicle is exhibiting any of the symptoms above and you’ve pretty much determined that you do have a bad brake caliper, fix it right away.
Also, you may hear some people talk about rebuilding brake calipers. But it’s the 21st century and replacement calipers are cheap and plentiful—no one overhauls them anymore. Just get a new or rebuilt caliper. It’s much easier.
And if you don’t feel up to replacing the caliper yourself, have a professional do the job for you. Once again, you don’t want to take any chances with your brakes.
What Does a Brake Caliper Do?
Brake calipers are fairly straightforward components. Most modern vehicles have a four-wheel disc brake system with a caliper at each wheel, while some cars have disc brakes with calipers in the front and drum brakes in the back.
When you push the brake pedal to apply the brakes, brake fluid flows to the individual calipers. The pressurized fluid forces a piston inside the caliper to squeeze a pair of brake pads against the brake rotor. Forcing the pads against the rotor creates the friction needed to bring your car to a stop.
Each caliper mounts (either directly or indirectly) to one of the car’s steering knuckles. A brake hose delivers pressurized fluid to the caliper.
Calipers also have bleeder screws that a mechanic can open to purge the brake system of air. They may have either one or two pistons, depending on the application.
There are two basic caliper designs: fixed and floating. Fixed calipers mount directly to the steering knuckle and do not move back and forth. Floating calipers (a.k.a. sliding calipers), on the other hand, mount to an adapter plate, which is bolted to the steering knuckle. A set of slider pins or bolts allow the caliper to slide back and forth as the brakes are applied and released.