Car brakes are one of the essential safety devices that are installed in cars, and there are different kinds of braking structures built into most cars. A few of them are the anti-lock braking system, the disc brake, the drum brake, and the emergency brake.
The brake caliper holds the piston and also suspends the car brake pads over the wheel rotor. The brake piston is linked to the brake pedal through the hydraulic lines.
Therefore, if the brake pedal is matched, a hydraulic force is transmitted to the piston, and the piston pushes the brake pad against the wheel rotor and causes friction. This friction slows down or brings the car to a stop.
The brake caliper mechanism retracts the brake pad from the wheel rotor immediately after the pedal is released.
Over time the brake caliper could start wearing off and will get worse and will require replacement. In this article, we’ll discuss at length the symptoms of a bad brake caliper, the diagnosis, etc.
What Is a Brake Caliper?
Bolted to the steering knuckle, a brake caliper has two basic jobs: housing friction material (the disc brake pads), and, transferring pressurized brake fluid from the master cylinder through a piston (or pistons) to clamp the brake pads against the disc brake rotor when you push on the brake pedal.
As the pressurized fluid acts on the caliper piston, it squeezes the disc brake pads against the disc brake rotors.
The energy of the pads pushing against the rotor generates heat from friction. This heat friction slows the rotor (and wheel) rotation, ultimately bringing your car to a stop.
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.
Symptoms of a bad brake caliper
The most common symptoms of a bad brake caliper include the car pulling to one side while braking, dragging brakes, and reduced stopping power.
You might also notice uneven brake pad wear, a soft or spongy brake pedal, strange noises, or even a burning smell caused by excessive friction. In some cases, a brake fluid leak may also be present.
Let’s take a closer look at these signs of a failing brake caliper and what they can mean for your braking system.
#1. Car Pulls To One Side When Braking.
When a caliper seizes, it won’t retract back into its original position. Therefore, it continues to push against the brake pad, leading to dragging along the rotor.
While the caliper is stuck, the vehicle inevitably pulls to the side, especially while braking, because the force is unequal. You may have to counteract the pulling by steering to the other side while braking.
#2. Dragging.
For the very same reason, you may also feel the car dragging on one side while driving. The stuck caliper pushes the pads into the rotor even when you aren’t braking.
It’s going to create a similar sensation to what it feels like when you have a foot on the gas and another on the pedal, even though you aren’t actually braking. Continuing to drive like this only creates unnecessary wear to the brake pads and rotors.
#3. Reduced Stopping Power.
According to the NHTSA, brake problems cause more than 20% of accidents. That’s why it’s so important to make sure your brakes provide the necessary stopping power they were designed to give you.
When any part of your brakes isn’t working as it was intended, braking power can be reduced. This puts you at a higher risk of an accident, so you don’t want to overlook the issue.
#4. Uneven Brake Pad Wear.
As the caliper pins stick, the brake pads will inevitably wear faster. With the brake pads engaged more than necessary, the material starts to wear prematurely.
It isn’t just the brake pads you need to worry about. Because the pads are dragging against the rotor, that surface is also going to wear down unnaturally.
#5. Brake Fluid Leak.
In normal operating conditions, you shouldn’t need to add any brake fluid. It remains intact in the braking system unless there’s a leak. When a caliper fails, fluid can start to leak around it. The fluid would be coming from the piston seal with the caliper activated.
In some cases, you may notice the brake fluid level dropping before noticing any other symptoms. A quick visual inspection would reveal where the fluid is coming from, leading you to the bad caliper.
#6. Soft or Spongy Brake Pedal.
The stuck caliper leads to a soft or spongy brake pedal, but usually, because the fluid is leaking. It can also be caused by air in the brake lines or occurs when the pads become overheated.
There’s also the chance that you are feeling a strange pedal because of the additional clearance. A seized caliper creates clearance between the pad and rotor, which makes the whole system feel different.
#7. Brake Noises.
As the brake caliper sticks, you may hear some interesting noises. If the problem stems from the brake caliper bracket breaking, you may hear clunking. This can also cause the wheel to lock up.
The brakes may also squeal, similar to what you hear when the pads are low. Yet, you may hear this noise even when the brake pedal isn’t depressed because the caliper is causing the pad to remain engaged.
If the problem gets too bad, both the pads and rotor are going to wear, eventually causing a grinding noise. This would be your last warning before brake failure occurs.
#8. Burning Smell.
The final warning sign is a burning smell. The burning smell created by a stuck caliper is unique because it’s reminiscent of the odor from overheating brakes. It’s not going to smell like burning electronics or an overheated engine.
With the brake pads constantly engaged, the material becomes too hot. The biggest problem after noticing this smell is that the brakes aren’t going to work as intended once they become too hot. This problem further leads to a loss of brakes.
Causes of a Bad Brake Caliper
A bad brake caliper can be caused by a range of factors, including:
- Worn or Damaged Brake Pads: Worn or damaged brake pads can cause the brake caliper to malfunction, leading to reduced braking performance.
- Brake Fluid Leaks: A leak in the brake system can cause the brake caliper to malfunction, leading to reduced braking performance.
- Worn or Damaged Brake Rotor: A worn or damaged brake rotor can cause the brake caliper to malfunction, leading to reduced braking performance.
- Corrosion or Rust: Corrosion or rust on the brake caliper can cause it to malfunction, leading to reduced braking performance.
- Manufacturing Defects: In some cases, a bad brake caliper can be caused by manufacturing defects, which can lead to reduced braking performance.
What happens if you drive a car with a bad caliper?
It is normal for brake pads to wear out over time under normal use, but they can also wear out quicker in certain circumstances.
Examples of those circumstances are aggressive stopping at high speed and brake pedal riding. Also, if the brake caliper goes bad, it can cause the brake pad to wear out quicker and may result in brake failure.
Suppose your brake structure starts wearing out; it normally sends out a signal to you. If you ignore these signals, you might be heading to a disaster that might be fatal.
Always observe and monitor your car brake system for abnormalities like loud squealing and Abs Light On.
Ensure you fix any potential breakdown of your brake system, like brake pad wear off and unresponsive brake caliper.
Continuous usage of a faulty brake caliper is dangerous and can cause catastrophic damage to the entire brake system. Below are some common effects of driving with a bad caliper.
#1. Damage to brake Wheel calipers and rotors.
The brake system is made of integrated moving components; therefore, if one of the components wears off, other devices connected with it will start wearing off too.
For instance, if your brake pad wears to a particular extent that the metal is exposed, it will start wearing down the wheel rotor and cause severe damage to it within a short period.
What happens is that when the brake pad squeezes and makes contact with the wheel rotor to halt the car, it grinds against the rotor.
If the brake pads are not replaced, the grinding continues to occur each time the brake pedal is matched and in a short period, the brake rotor will be damaged. The grinding noise is a clear indicator that something is wrong.
Whenever the brake pads are pushed against the brake disc, it generates heat. And the heat damages the seals on the piston and makes it get stuck. This is what causes brake calipers to fail to return when the brake pedal is released.
#2. The increased brake response period.
The efficiency of your brake pads is completely reduced when they are worn out. Therefore, it is necessary to always observe your brakes and take note of the time they take to respond.
Note that if your brake pad starts wearing off, your brake may not answer once you depress it. You may have to pump it before it engages.
Some of the consequences of driving with a bad caliper include slippery brakes car sliding one corner when you apply the brake.
Finally, the brake bad may stop engaging and disengaging the brake rotor as built by the manufacturer, and it might result in brake failure.
#3. Car trembles when the brake is applied.
Car vibrations or trembling occur due to so many reasons, especially from the wheel area. Therefore, here comes an important question; can a bad brake caliper cause vibration?
Yes, it can because a vehicle whose brake is working properly should respond smoothly when the brake is applied.
So, when the pad and the rotor have been damaged or worn out excessively, they could start causing vibrations in the car’s movements. Your steering may also vibrate when you try to slow down or make a stop.
#4. Tiers may start wearing down.
If you fail to fix your car brake mechanism when some parts are bad, then your tires will also start wearing down.
When you have uneven deceleration amongst your tires due to a bad brake caliper on some of the wheels, then some tires will wear off quicker. A bad caliper also causes you to slam your brake pedal repeatedly to achieve a stop.
How Do You Diagnose A Brake Caliper?
Caliper diagnosis isn’t as difficult as you might think. If you’re ready and willing to get dirty, there are several methods you can use to troubleshoot a bad caliper.
Note: The following are general guidelines for educational and entertainment purposes only. Consult your vehicle’s factory information for specific repair instructions and recommended safety procedures.
#1. Inspect for Leaks.
Got a low or spongy brake pedal? One of the most common causes is a leaking caliper, so the first step in your diagnosis is to look for leaks. Check the areas around the caliper piston as well as the bleeder screw for signs of fluid loss.
#2. Look at the Brake Pads.
A stuck brake caliper or sticking caliper sliders can cause uneven brake pad wear. To check for this, safely raise and support your vehicle, remove the caliper and take a look at your brake pads.
Is one pad much thicker than the other? If your car has floating calipers, uneven pad wear usually indicates that the slider bolts or slider pins are sticking. Check that the sliders move freely. If they don’t, clean and lubricate them to restore proper operation.
If you find uneven pad wear, but the sliders are OK (or your car has fixed calipers without sliders), you’ll want to move on to the next step: checking caliper piston operation.
#3. Check Piston Operation with a Tool.
A stuck piston is another common caliper problem. A piston that’s stuck in the applied position (out of its bore) can cause brake drag, uneven brake pad wear, and a vehicle that pulls to one side.
There are a few ways to check for this condition. Start by safely supporting the vehicle on jack stands and attempting to turn the wheel/tire assembly by hand. If the wheel is hard to turn, you may have a caliper that’s sticking and pushing the pads against the rotor.
You can also check the caliper piston by trying to push it back into its bore. Here’s how it’s done:
- Start by safely raising the vehicle and supporting it with jack stands.
- Remove the wheel and tire assembly.
- Unbolt the brake caliper from the mounting bracket and pull it away from the rotor. Do not unbolt the brake hose.
- Use a large C-clamp or disc brake spreader to push the piston back into its bore. When doing this, keep an eye on the master cylinder to make sure fluid doesn’t get pushed out of the reservoir.
Note: Some calipers require a special wind back tool to push the caliper piston back into its bore. This tool is often required on rear calipers that have an integrated parking brake. Also, in some instances, a scan tool is required to put the brake system in service mode. Consult the factory repair information for your vehicle before performing this test.
- A good caliper piston should be able to push back until it’s completely seated in its bore. A bad caliper piston, on the other hand, will be difficult or impossible to push back.
But wait – if the caliper can’t be pushed back into its bore, how do you rule out a restricted brake hose? Crack the bleeder screw on the caliper and try pushing the piston back into its bore. If the piston still doesn’t move, the caliper (not the hose) is probably to blame. It’s also possible that the bleeder screw is restricted.
Warning: After reinstalling the brake caliper, make sure to pump the brakes until they’re firm. DO NOT drive the car until the brakes feel solid.
Only pump the brakes after everything is reassembled and the car is on the ground. If you pump the brakes with the caliper removed, the caliper piston will come shooting out.
#4. Check Piston Operation with a Buddy.
A piston that’s stuck in the retracted position (inside its bore) can cause problems such as a low brake pedal.
If you have a friend handy, you can check that the piston moves both in and out properly. Simply have your buddy apply the brakes while you monitor caliper operation.
- Start by safely raising the vehicle and supporting it with jack stands.
- Remove the wheel and tire assembly.
- Have your assistant push the brake pedal.
- Watch the caliper piston come out of its bore and push the brake pads against the rotor.
- Have your assistant take their foot off the brake pedal.
- Watch the caliper piston return into its bore.
Not only does this procedure ensure that the caliper piston is moving inward, but it allows you to see if the piston is moving outward as well.
#5. Attempt an Advanced Line Lock Test.
But wait – there’s more. Although some DIYers shy away from the more advanced line lock test (because the brake hoses can be damaged), it’s sometimes used by professionals.
When there’s a soft brake pedal concern, this method can be useful for isolating a bad caliper. A special brake hose pinch tool (a.k.a. line lock tool) must be used to prevent damage to the brake hoses. A set of regular vise grips should not be used.
The process involves pinching off the brake hoses from the calipers one at a time. If the brake pedal firms up when one of the hoses is pinched off, the corresponding caliper may be faulty. You’ll want to inspect it further for leaks and other issues.
How to Fix a Brake Caliper?
This section provides detailed instructions on how to address a leaking brake caliper. We’ll focus on replacing the seals, which is the most common repair.
#1. Prepare Your Vehicle and Remove the Wheel.
- Loosen Lug Nuts: While the vehicle is still on the ground, use your lug wrench to slightly loosen the lug nuts on the wheel you’ll be working on. Don’t remove them yet.
- Lift and Secure: Jack up the vehicle and place jack stands securely under the frame. Remove the lug nuts and the wheel.
- Open Master Cylinder Reservoir: Remove the cap from your master cylinder reservoir. You may want to use a syringe to remove some brake fluid, especially if the reservoir is full, to prevent overflow when compressing the piston later.
#2. Disconnect the Brake Line and Remove the Caliper.
- Locate Brake Line: Identify the brake hose leading to the caliper. Have your drain pan ready underneath.
- Disconnect Banjo Bolt: Using an appropriate wrench, carefully loosen and remove the banjo bolt that connects the brake hose to the caliper. Be prepared for fluid to drip out. Place the old crush washers aside.
- Secure Brake Line: To minimize fluid loss, you can often use a specialty brake line clamp (if available) or simply elevate the hose higher than the master cylinder.
- Remove Caliper Mounting Bolts: Locate the two caliper mounting bolts (often on the back of the caliper). These might be large hex bolts or smaller Torx/Allen bolts. Use your socket wrench to remove them.
- Remove Caliper: Carefully slide the caliper off the brake rotor. Support it to avoid stressing the brake line if it’s still connected. If the brake line is disconnected, set the caliper on a clean surface.
- Remove Brake Pads: Remove the old brake pads from the caliper bracket or the caliper itself. Inspect them for uneven wear or contamination.
#3. Rebuild the Caliper (Replace Seals).
This is the core process for how to fix a leaking brake caliper by addressing the internal seals.
- Remove Old Piston(s):
- If the caliper is still connected to the brake line, you can try to pump the brake pedal very gently to push the piston out. Be careful, as it can pop out forcefully. Catch it with a rag.
- If the caliper is disconnected, you can use compressed air (with extreme caution and PPE) through the brake line port to push the piston out. Again, be ready for it to pop.
- Alternatively, use sturdy pliers to gently wiggle and pull the piston out. Avoid scratching the piston or bore.
- Inspect Piston and Bore: Thoroughly clean the piston and the caliper bore with brake cleaner. Look for any pitting, rust, or deep scratches. If the piston or bore is heavily corroded or damaged, a rebuild kit might not be enough; you may need to replace the entire caliper.
- Remove Old Seals: Use a small pick or screwdriver to carefully remove the old piston seal (the square-cut rubber ring inside the bore) and the dust boot from the caliper. Be gentle to avoid scratching the caliper bore.
- Clean Caliper: Use a wire brush and brake cleaner to clean any rust or debris from the caliper, especially around the piston bore and slide pin areas.
- Install New Seals:
- Lightly lubricate the new piston seal with clean brake fluid. Carefully seat it into its groove inside the caliper bore. Ensure it’s not twisted.
- Install the new dust boot. It typically has a groove that fits into a channel on the caliper body.
- Install New Piston:
- Lubricate the new piston (or your cleaned original piston if it’s in good condition) with clean brake fluid.
- Carefully slide the piston into the caliper bore. It should go in smoothly.
- Ensure the outer lip of the dust boot fully seats into the groove on the piston. Use a flat, blunt object (like a socket) to gently push the piston fully in, making sure the dust boot stays properly seated.
#4. Reassemble and Reinstall the Caliper.
- Lubricate Slide Pins: Clean the caliper slide pins (if applicable) and apply a generous amount of high-temperature brake grease. Ensure they move freely.
- Install New Brake Pads: Install your new brake pads into the caliper bracket. Apply a thin layer of brake grease to the back of the pads where they contact the caliper piston and mounting points (not the friction material!).
- Mount Caliper: Slide the caliper back over the rotor and align it with the mounting points. Install the caliper mounting bolts and tighten them to your vehicle’s specified torque settings. This is where a torque wrench is crucial.
- Reconnect Brake Line: Install new copper or crush washers on either side of the banjo bolt. Reconnect the brake hose to the caliper with the banjo bolt. Tighten it to the manufacturer’s torque specification.
#5. Bleeding Your Brakes And Final Checks.
This is a critical step to ensure proper braking function after any brake system work.
- Refill Master Cylinder: Top off the master cylinder reservoir with the correct type of new brake fluid. Keep an eye on the level throughout the bleeding process.
- Bleed the Caliper:
- Start with the caliper furthest from the master cylinder (usually the passenger rear).
- Attach a clear hose to the bleeder screw and submerge the other end in a container of clean brake fluid.
- Have a helper slowly press and hold the brake pedal.
- While the pedal is held down, open the bleeder screw with your bleeder wrench (about 1/4 to 1/2 turn). You’ll see fluid and air bubbles escape into the hose.
- Before the pedal reaches the floor, close the bleeder screw.
- Then, tell your helper to release the pedal.
- Repeat this process until no more air bubbles come out of the hose, and the fluid runs clear.
- Move to the next furthest caliper (driver rear), then passenger front, then driver front.
- Check for Leaks Again: Once bleeding is complete and all bleeder screws are tightened, visually inspect all connections (banjo bolt, bleeder screw) for any signs of leakage.
- Test Brake Pedal: Pump the brake pedal several times. It should feel firm and consistent. If it’s still spongy, you likely have air in the system and need to re-bleed.
- Reinstall Wheel: Mount the wheel back onto the hub, hand-tighten the lug nuts, lower the vehicle, and then torque the lug nuts to factory specifications in a star pattern.
Changing a brake Caliper
Changing a brake caliper is a fairly simple task for someone with basic mechanical knowledge, but make sure you leave enough time to fully drain and bleed the brake system safely.
Tools you will need
- Spanners
- Brake turning tool
- Socket set
- Jack
- Pliers
- New brake pads
Step 1: Remove the old Caliper.
Preparation
- Loosen the wheel nuts before lifting the car
- Jack up the vehicle as if changing a tire
- Remove the wheel to access the brake caliper
Disconnect the brake line
- Locate the faulty caliper
- Remove the brake fluid line
- Place the open end into a bowl or suitable container
- Allow the brake fluid to drain safely
Remove the Caliper
- Undo all mounting bolts and fixings
- Remove the caliper from the assembly
Step 2: Prepare the new Caliper and piston.
- Use a brake turning tool to compress the piston on the new caliper
- Continue until the piston is fully compressed and the tool can’t be turned any further
- Once fully compressed, attach the brake line
- Do not fully tighten the brake line yet
Step 3: Fit new brake pads and install the Caliper.
Brake pads
- Always fit new brake pads with a new caliper
- Do not reuse old brake pads
Install the Caliper
- Lightly oil all bolts and fixings
- Position the new caliper on the assembly
- Tighten all mounting bolts securely
Check hose alignment
- Make sure the brake hose isn’t twisted
- Ensure it’s clear of all moving parts
- Once aligned correctly, fully tighten the brake hose
Step 4: Bleed the brakes.
- Check that the master cylinder is full of brake fluid
- Attach rubber tubing to the bleeder valve on the caliper
- Ask an assistant to press down on the brake pedal
- Allow air to escape through the bleeder valve
- When no more air comes out:
- Close the valve
- Refill the master cylinder as needed
Step 5: Final checks and test drive.
- Reattach the wheel
- Lower the car back onto the ground
- Tighten the wheel nuts fully
- Take the car for a gentle test drive
- Apply the brakes slowly at low speeds to check:
- alignment
- brake response
- overall readiness
Preventing Caliper Failures With Routine Maintenance
To prevent brake caliper failures, regular maintenance is essential.
- Start by performing routine checks of the brake system, including inspecting the brake pads and rotors for wear, and ensuring that the calipers are functioning properly.
- A brake fluid flush should be done every two years or according to your vehicle’s manual to remove old, contaminated fluid that can corrode calipers and reduce braking efficiency.
- Ensure the guide pins are properly lubricated during brake services. This lubrication prevents the pins from seizing, ensuring even pad wear and smooth braking.
How Much Does It Cost To Replace A Brake Caliper?
On average, expect to pay between $500 and $800 to have a brake caliper replaced. This estimate depends heavily on what type of vehicle you drive and the local labor costs. If you can replace the caliper yourself, you may only spend $200 to $550 for the parts.
There’s also the option to rebuild the caliper. While this lowers your repair costs, it does take some time to perform. To rebuild the caliper, you need to install new seals, pin sleeves, pistons and guide pins.
FAQs.
Q: How Often Should Brake Calipers Be Inspected?
You shouldn’t wait until you notice problems. It’s best to inspect your brake calipers every 12,000 miles or during routine maintenance. Regular checks help guarantee your vehicle’s safety and performance are always at their best.
Q: Can I Drive With a Faulty Brake Caliper?
You shouldn’t drive with a faulty brake caliper. It can lead to decreased braking performance and increased risk of accidents. Get it checked out immediately to guarantee your safety and the safety of others on the road.
Q: What Causes Brake Calipers to Fail?
Brake calipers can fail due to wear and tear, corrosion, or lack of lubrication. Overheating from excessive friction or contaminated brake fluid also contributes.
Regular maintenance helps prevent these issues and guarantees your vehicle’s braking system functions properly.
Q: Are There Different Types of Brake Calipers?
Yes, there are different types of brake calipers. You’ve got fixed and floating calipers, each with distinct designs and functions. Choosing the right type can enhance your vehicle’s braking performance and overall safety.
Final Words
Driving with a bad caliper is wrong and very dangerous, especially when they have excessively worn out.
A bad caliper can cause damage to the wheel rotor, wearing of car tires, car vibration, and reduced brake response time, and it may even lead to a severe road accident. Therefore, always watch out for symptoms of a bad brake caliper and fix it on time.
Also, conduct a proper diagnosis on your brake system to ascertain the particular damaged part and service it or replace it if needed.
Inspect for leaks, inspect brake pads, inspect piston and hydraulic lines, and service or replace them. Always call your mechanic to carry out proper diagnosis and repair unless you understand the issue you’re facing at the moment.