Bad Brake Caliper Symptoms
Your brake system relies on a number of moving parts to achieve consistent, safe braking. When a single part is damaged or needs maintenance, it can affect your braking in a number of ways. Brake calipers can often hide their issues in a number of ways, and overlooking them can cause the average DIYer to continue to perform other repairs, when the caliper was at fault all along. Find out when to replace brake calipers on your vehicle by using these five common signs that they need replacing.
Brake Calipers Explained
You may be used to replacing your brake pads, but brake calipers also need to be replaced, as over time they lose their ability to clamp and relax the brake pads when the pedal is depressed and released. Calipers house a powerful piston that uses the pressure of the hydraulic brake fluid to press brake pads against the brake rotor. When working correctly, your calipers glide in and out effortlessly as you press the brake pedal – applying pressure when you press the pedal, and relaxing just enough to allow no slack in the pedal when not in use.
Whether you have fixed or floating calipers, the same signs of damage apply. Pull into your garage and inspect your brake pads, calipers, and rotors for signs of damage or malfunctioning. Floating calipers are particularly susceptible to sticking and are by far the most common calipers. Fixed, multi-piston calipers can have issues as well though. Look carefully at your entire brake system before blaming your calipers. A car’s brake system relies on a number of components for smooth braking, so any issue with your brake pads, rotors, brake fluid, or other component can produce similar signs of bad braking.
Most vehicles have a series of sensors that alerts you to a brake malfunction. The brake light indicates when sensors detect something wrong with the system, but that system in most vehicles is very limited. The brake light will often trigger on low brake fluid, pressure, or pads that are worn down to the point of needing replaced – if your car is equipped with pad sensors. In a perfect world, your brake light would always illuminate at the first signs of trouble and you could safely repair your brake system before losing any braking power or efficiency.
Unfortunately, this isn’t always the case. Inspect all the relevant brake components for an issue. This light may also be caused by an electrical issue or damaged sensor.
Identifying and Preventing a Bad Brake Caliper
Unusual Noises, Smells, or Pulling
The first diagnosis of a bad brake caliper can be done while driving. A malfunctioning caliper issue can cause your vehicle to pull to one side as you brake. This is due to unbalanced braking. When one caliper works and another doesn’t, your vehicle will jerk to one side as you attempt to slow down or come to a complete stop.
Squealing, grinding, and metallic scraping noises while braking are all signs that your brake pads are probably worn thin. At this point, it’s just a matter of determining whether the pads are simply near the end of their life, or did a caliper cause premature failure. At the same time, a stuck caliper that is applying constant pressure to a brake pad or pads will cause that side of the car’s braking system to get extremely hot. This is often noticeable when you get out of the car and smell a burning chemical smell near one of the front wheels. This is the brake pad material’s bonding agents that are super-heated and giving off this smell.
Open-Wheel Resistance Test
During inspection or replacement of brake pads, one of the quickest and easiest ways to check if both calipers are relaxing properly is to simply test open-wheel resistance. In the old days, this is the way that you would test your drum brakes to insure that both were adjusted properly and at the same consistency. Once the vehicle is jacked up and secured, gently turn both front wheels. On a 2WD car, this should be easy, and both tires should turn with just a slight amount of resistance, and the SAME resistance. You should also hear the brake pads just barely pressing against the rotor. On a 4WD or AWD vehicle, you may need to put the vehicle in neutral or the transfer case in neutral to allow the front wheels to turn. Check the resistance of both wheels as you slowly turn them. If one wheel encounters more resistance to turn than the other, this side’s brake caliper may be suspect. Keep in mind, some calipers can intermittently stick or hang-up, and if that’s the case, if it’s not hanging up at this time, both wheels will not encounter different resistance.
The next step, regardless of whether you are changing pads or not, is to inspect the system carefully. When installing new brake pads, inspect the old pads very carefully. On a properly functioning caliper, the brake pads – both inside and outside on each side should wear at relatively the same rate. If one pad is noticeably worn out compared to the other three, the caliper is usually the suspect. Likewise, if one side has both pads far worn out compared to the other side, a caliper is also suspect. A brake pad should also wear evenly across the pad itself, where as one section of the pad – an outer edge, should not be worn more than its opposing edge – indicating a pad that is not pressing flat against the rotor.
Remember, after applying brake pressure in a braking situation, a caliper needs to relax when the pedal is lifted. In order to do that, the fluid and piston of the caliper has to properly retract, and in a floating-style caliper, the guide pins that make the caliper properly “float” in between the rotor need to move and relax when the caliper does. If any of these things don’t happen, the caliper will continue to apply slight pressure to the rotor, and ultimately wear one or both pads out.
One of the most common situations that reveals a bad caliper is when the brake pads have very recently been replaced, only to suddenly hear grinding again several months later. The inspection reveals 3 near-new brake pads, and one completely worn down to the metal. Many times, the owner assumes that something is somehow wrong with the brake pad, when in fact, the caliper was not relaxing and continued to apply pressure on this one brake pad, until it was completely worn.
A caliper can fail in a multitude of ways, and many times those failures aren’t noticeable immediately.
First, when removing the caliper, inspect the guide pins. In most calipers, these guide pins secure the caliper to the caliper hanger, and need to glide in and out effortlessly. The pins need to be cleaned thoroughly and properly lubed with brake grease before reassembly. Failed guide pins will usually become seized or extremely difficult to remove. Often times, the grease in them is baked solid, or is full of rust. Inspect the guide pin boots too as these boots seal and protect the guide pin. The caliper piston should retract when applying adequate pressure. If the piston is stuck, or difficult to push in, the caliper piston’s bore is likely corroded and needs to be replaced. Keep in mind, even if the piston does push in but required more work than normal, the caliper has to be able to relax easily when pressure is not applied – so just because the piston pushed in does NOT mean the caliper is good!
Check the hanger assembly carefully for cracks or damage, especially around the guide pins. If the guide pins ride in the hanger, check that the bores are clean of old, nasty brake grease. One trick to remove solid, old grease from a guide pin bore is to use a drill bit of exact equal size as your guide pin. Run the drill bit by hand down into the hanger bore to break up the old, solid grease and rust. Be sure not to physically drill into the metal itself, you are just using the bit to clean the edges of the bore. Then, flush the bore with brake parts cleaner.
If your caliper fails any of these visual inspections, it’s a good idea to replace the caliper. Keep in mind, many calipers do not come with the replacement hanger, so if your hanger does have signs of failure issues, you will need a semi-loaded caliper, or replacement hanger.
Luckily, several actions during the brake job, along routine maintenance can be done to ensure your calipers and braking system lives a good life.
For one, floating calipers need to be properly lubricated and completely clean on the guide pin and guide pin bore. Make sure when selecting a brake grease, you use one approved for braking systems that can with handle the heat and abuse it’s going to see over a long time in the braking system. It is vitally important that the guide pins are given the proper attention. Replacements can be obtained if the ones you have cannot be cleaned. It is recommended that the boots are replaced at every brake job. A failed boot will allow water into the guide pin bore, and eventually seize.
Many caliper piston failures occur because of corrosion in the piston bore. This is caused by water in the brake fluid, which is caused by a lack of flushing your brake fluid in regular intervals. Check out our other blogs on why flushing your brake fluid is vitally important. Remember, if you’ve just changed brake pads in the last year and have already encountered brake pad failure again, the chances are very likely that a caliper is suspect that was missed in the initial inspection.
Now that you know the top five signs of damaged brake calipers, you probably have many more questions. Here are some helpful FAQs as you determine the best course of action, given your unusual braking situation. Use this information to assist you in selecting the best brake components and successfully repairing your brake system.
How Often Do I Need to Replace My Calipers?
Unlike brake pads, it’s very difficult to identify the exact replacement schedule for brake calipers. When they operate effectively, brake calipers can continue to work for far longer than brake pads. A small piece of debris or unusual braking incident is all that’s needed to damage your calipers. Inspect them every time you replace your brake pads, but don’t replace your calipers unless there is something wrong with them. Follow any manufacturer guidelines when it comes to replacing calipers.
Should I Rebuild or Replace My Calipers?
Caliper rebuild kits are available for most makes and models of vehicles. However, unlike your engine or transmission, a brand-new caliper isn’t a major investment. Modern calipers are affordable enough to justify purchasing a complete caliper instead of a rebuild kit.
Rebuilding a caliper typically involves replacing the pistons, seals, pin sleeves, and guide pins. This process can take a significant amount of time and still has plenty of room for error. Unless your particular caliper is no longer being manufactured, it’s better to replace the entire component than to settle for a rebuild.
How Do I Maintain a Floating Caliper?
Floating calipers are particularly prone to seizing and sticking if not properly lubricated. Periodically inspect your floating caliper and grease it with brake lubricant to prevent a sticking caliper pin. This simple maintenance tip can prevent damage to the entire caliper and excessive wear on your brake pads.
Find Reliable Calipers Today
Now that you know the top signs of a bad caliper, learn more about how to tell if brake caliper is bad by discussing your issue with an AutoZone associate. Whether you stop by your local store or chat online with a qualified agent, find the information and parts you need. Don’t let a minor grinding noise lead to major brake failure, use these signs to solve your caliper issue and enjoy smooth, safe braking with reliable replacement calipers.