One of the most common complaints always reported by drivers is that they often hear brake noise when braking slowly. Such sounds as scraping, squealing, and squeaking may lead to vibrations, especially noise when braking at a low speed.
When your brakes are not functioning properly, they are one of the most perceptible parts of your car in terms of the sound they make. Brakes are prone to making sounds, but when you start noticing a high-pitched squealing or squeaking sound when you use them even at low speeds, that’s a clear sign something is not okay and ought to be addressed.
In this article, we’re going to learn the common causes of brake noise when braking slowly and the possible solutions to the problem. But before we do that, it’s essential you first grasp how the braking system works.
So, let’s get started…
How The Braking System works
The braking system is a car’s most significant safety tool. The system has various parts with which it works toward achieving a similar goal – To stop the wheels of the vehicle and hence stop the car.
Every brake works under the principle of friction. Opposing force is something friction does, but we increase it using brakes. Friction converts the kinetic energy into heat, which eventually brings the vehicle to a halt.
All vehicles have brakes on all four wheels that are operated by a hydraulic system. The brakes are either a drum or disc type. Most vehicles have four-wheel disc brakes, however, others have drums for the rear wheel and discs for the front wheels. But since the massive responsibility of stopping a car relies on the front brakes, the more effective disc brakes are installed on the front wheels.
The brake system works in various ways.
When you hit the brake pedal, the force generated by your leg is amplified numerous times by mechanical leverage. It’s then amplified more by the action of the brake booster. The piston enters the cylinder and squeezes the hydraulic fluid out of the end.
Hydraulic fluid is then distributed around the whole braking system within a system of brake hoses and lines. Afterward, pressure is then distributed equally to all the brakes. The force generated generates friction between the disc brake rotors and brake pads, which stops the car.
During this process, you may hear brake noise when braking slowly, which in most cases points to a defect in one of the braking elements.
Understanding Brake Noises For Proper Diagnosis
Before we jump into the causes and solutions, understanding various brake noises will help you gauge the severity of a brake problem. Learn what grinding, scraping, and squeaking sounds signify.
Brake Grinding
Grinding noise from the braking system is a red flag; it’s always a serious problem. Grinding brake noise when braking slowly means that all your car brakes are used up. The only thing left is the rotor and the caliper. The minute you notice your car brakes grinding at low speed, stop your vehicle
Immediately head on to the nearest service center for help. If you leave your brakes to grind before servicing them, you’ll be left in a worse situation. The repair will be more costly.
Squealing
Squealing brake noise when braking slowly is often a result of parking your car outdoors in a wet area. When metal surfaces get in touch with water for a long period, they start to develop rust. And that’s the case here.
However, after driving for some time, the rust diminishes. And after a few brakes, the creaking sound when braking slowly might even disappear. Nevertheless, it isn’t a good idea to park your car in a wet area.
Squeaking
Squeaking sound often results from low-quality brake pads. You see, low-quality brake pads have huge metal flakes in them. So, it comes in contact with the rotor, hence producing noise. Always opt for quality brake pads in the first place.
Besides that, the moment you hear the sound, it means your rotor is constantly getting damaged. The brake’s wear indicator will let you know when you need to change your brake pads.
Brake Noise When Braking Slowly: Why Does It Happen?
Now that you’re aware of the types of noises, let’s delve right into the reasons to help you figure out the right solution.
1) Worn Out Brake Pads
One of the common reasons for brake noise when braking slowly is having worn-out brake pads. Brake pads are manufactured from a mixture of copper, iron, and graphite. All these things are bonded together to form a brake pad. But with time, they get worn out.
That’s when the outer metal of the rotor and the clipper comes in contact, resulting in the said noise. So, if you’ve used your brake pads for a long time or have worn them, go and change immediately. Failure to do so will result in severe damage to your brakes. Besides, the caliper and the backing plate can destroy each other, causing grooves and damage.
2) Moisture
Occasionally, you may notice that your car brakes squeal after rain or on a particularly humid morning when you start driving. That’s usually caused by moisture in the brake assembly, around the rotor and brake pad. Water may inevitably get in there eventually, but if it’s not affecting your brake’s performance, just the sound it makes, it may not be a cause for concern.
If it happens more often and even during mornings when it’s not moist, then you may have a problem that ought to be addressed.
When it happens, it results in the formation of a thin layer of rust around the rotor. Upon applying brakes, the thin layer of rust is scraped off as rusty debris, which ends up being the source of squeal in your brakes.
3) Debris
Just like water finds its way into the braking system, so do foreign substances like dust, dirt, grease, etc. Brake pads, calipers, and rotors are frequently exposed to dirt and dust from the road surface.
These contaminants get trapped between the brake pad and rotor surfaces, causing a hissing or squealing brake noise when braking slowly.
The build-up of foreign substances on the braking surface may also increase the amount of force the pads apply to the rotors when braking. If this happens, it can lead to sticky, noisy brakes, especially at low speeds when the temperature of brake pads is higher than usual.
A small amount of rust on the rotor surface is expected if the vehicle has been parked for a few days and often wears out rapidly upon the application of brakes a few times at high speeds. However, the rust may stay on the rotors even longer if the brakes are only applied at lower speeds.
4) Broken Shims
These are basically metal adhesive or thin rubber that sit between the caliper and the brake pads to eliminate any sounds. Therefore, it’s pretty apparent what happens when the shims get broken.
A worn-out shim will make contact with a piece of the braking system, such as the rotor. When there is a metal-to-metal contact like this, you’ll hear a grinding sound from your braking system. So, anytime you get a brake job done, make sure to replace the shims.
5) Material
The type of material that your brake pads are made of has a significant impact on the noise produced by your brakes when you apply them. Since brakes need to absorb a lot of friction, they should handle substantial heat over time. Asbestos was once the desired choice for brake lining but was phased out because it was carcinogenic and hence dangerous to use.
When asbestos was eliminated, other materials came into play, including Kevlar, ceramics, and other metal blends. Kevlar can be dusty and sometimes lead to squeaking sounds in the brakes. However, other metals and ceramics used can also result in such sounds as squealing, grinding, and hissing. These are just minor annoyances. They aren’t necessarily an indicator of an issue with the brakes. Your brakes will still work fine when these sounds occur; it’s just the kind of annoyance to deal with.
Other low-quality brake pads are made with high-quality metal content. It’s important to note that most brake pads have some degree of metal in them, but the cheaper ones have large quantities, which can easily damage your rotors with time. When the metal entrenched in the pad material squeezes against the rotors, you will probably hear a squealing sound, especially when slowing down, which can potentially last the entire life period of the pad.
When you want to replace your brake pads, you ought to make sure you are focused on the ones with more organic material. Resin, rubber, fiber, Kevlar, and so on are all materials that make up a brake pad and are less annoying and damaging in terms of producing sounds you don’t want to hear.
If the problem persists, you could have the issue recalibrated, and a mechanic could possibly disassemble the assembly and change the harmonics. That may seem a risky path to take, but if the problem is bad enough, you may want to consider it.
6) Worn Out Rotor Discs
Worn-out rotor discs may result from braking using low-quality or worn-out brake pads, which scratch the rotor surface. After a while, the flat surface of the rotor will be distorted, hence causing a squeaking sound. Rotor discs that are extensively worn out may form scraping sounds instead.
Another reason for deflecting the rotor surface is washing your vehicle and exposing the rotors to cold water when it’s still hot. This leads to the deflection of the surface, and you’ll hear noise and vibrations when braking. These vibrations occur in irregular forms and can easily be felt through the brake pedal.
7) Unlubricated Caliper Screws
Failure to lubricate the caliper screws and bolts cause a grinding brake noise when braking slowly. This hardly occurs, but it could. If it happens, ask your mechanic to replace the caliper bolts for you.
8) Faulty Wheel Bearing
When you hear noises or vibrations from your wheels that alternate from quiet to loud, you probably have a damaged or worn-out wheel bearing. Therefore, carefully check the wheels and replace them if need be to avoid annoying sounds.
Diagnosis Of Brake Noise Problems
If you experience brake noise problems with your car, it’s important to diagnose the problem yourself even before taking it to an auto repair shop. Here are various ways to perform some checks to ascertain the source of the problem.
Step #1: Find Loose Parts
The initial step is to take apart your car’s front wheels. Perform a simple check by shaking the rotor, pads, calipers, and other brake components. All these parts shouldn’t be moved by hand. If there are any vibrations, there are a few loose, damaged, or missing bolts and clips. You ought to fix that immediately. Failure to do so leads to even more vibrations and noise braking.
Step #2: Apply Dampening Paste
Extreme vibrations from braking parts often lead to lousy brake noise when braking slowly. After fixing the loose or damaged bolts or clips, you will want to apply damping paste – a water-based compound extremely effective in reducing noises and vibrations from your braking parts.
Apply dampening paste on the metal part of the brake pad (at the back of it) between the caliper piston and the brake pad. Allow the paste a significant amount of time to dry (between 2 to 3 hours or till it dries off completely) before you reassemble the brake unit. This enables it to become sticky and darker.
Step #3: Examine The Brake Shoe Or Brake Pads
Examine the brake pads for replacement or wearing out. Most drivers find this quite challenging when driving. Most brake pads have a wear indicator designed to alert you when it’s worn out. Since aftermarket brake pads come in different sizes, they tend to wear out unevenly. This, in turn, makes the pad ride the edge of the rotor resulting in logical brake noise so you can hear noise while braking, but the pads are in good condition.
In that case, you can smoothen the lip and make it even to increase the brake pad’s lifespan and get rid of the noise. If it means having to replace your brake pad, make sure to get the correct pad. New brake pads can make noise as well until the pads are at the rotor surface shape.
Step #4: Examine The Brake Rotor
When using your car and changing the brake pad, your rotors may be affected by this process. It may result in an uneven brake rotor, causing the brake pad to jump and wiggle.
You ought to have an extremely smooth rotor surface. Therefore, if the rotor wear is not that profound, you may be prompted to have your rotors machined to smoothen the surface. Make sure to check your rotor’s thickness before performing this procedure because it may affect your braking’s safety. But if the wear is extreme or the whole rotor isn’t thick or is distorted, you will have to replace the rotors immediately.
Step #5: Conduct An Extra Check
It’s always important to check the brake lines and the brake oil after conducting maintenance in your braking system. Check its level, and if it’s below the marked level, you need to fill the right oil up to the marked level.
Besides, also ensure to check your brake fluid color. If it is anything else apart from bright and clear, then you need to change it as soon as possible. Probe for any signs of leakage in the brake line and if you happen to locate one, replace it immediately.
What Is The Cost Of Repairing A Noisy Brake?
Sometimes, the brake noise may become unbearable or make you feel like it’s causing a decrease in your overall brake performance. In that case, it’s advisable to get your brakes repaired. Even if they aren’t faulty, the sound generated can be so annoying to justify having your pads replaced.
The cost of replacing your pads goes per axle. Therefore, you would generally replace either the back brakes or the front brakes at the same time. You could do it all at once, but that will hike the price.
The average cost of replacing brake pads typically ranges between $150 to $300 per axle. However, this may vary significantly according to the type of brake pads you’re using. Ideally, better brake pads cost an average of $30 or more, depending on the material used.
Can You Repair Your Own Brakes?
Just like any other repair job, you can repair your brakes if you wish to. For instance, changing the brake pads isn’t a difficult task if you’re comfortable working on your vehicle’s repair. You need to keep in mind that there are various causes for squeaking in your brakes and just problems with the pads.
There are also numerous guides online, such as the one below, that can help walk you through a detailed process of repairing your brakes, so you know exactly what you need and ensure you don’t miss anything.
You need to ensure that you have jack stands, a floor jack, and a brake to get the job done. It also helps to properly position the brake caliper piston to the new brake pads. It’s also vital to make sure that the brake pads are accurately fixed when switching to the new ones.
You don’t want pads that are just installed and don’t correctly fit or adjusted, as this may lead to clamping down of the pads on the rotor when pressing the brakes with your foot. However, this is one of the rare tools used, and many people who don’t spend most of their time doing brakes lack one of these in their toolbox despite its cheap price.
Most drivers are dreaded by the idea of fixing their own brakes because of the fear that they may do something wrong, and the brakes are the last thing you want to fix wrongly. In that case, there’s no harm whatsoever in getting your car to an auto repair shop for repair rather than trying it on your own.
There are certain things you need to consider when fixing your brakes. So if you are not comfortable performing this fixture, you should leave it to the experts that you can count on to ensure nothing goes wrong.
How Can I Maintain My Car Brake System?
Maintaining your car is a bold step toward saving money rather than taking your vehicle to an auto repair shop only when an issue arises. Your vehicle should be well checked and maintained even before an accident. When the vehicle undergoes regular inspection, you are sure your brakes are roadworthy. Here are steps to maintain your vehicle’s braking system.
- Examine your brake fluid levels every three months. Your car’s brake fluid ought to be replaced every 30,000 miles or two years.
- Change your brake discs when need be according to your driving style and environmental conditions. Change them at intervals similar to a normal vehicle. Sports car brakes ought to be replaced every 20,000 miles. A regular car’s brake discs would naturally last a lot longer than that.
- Get your rotors and brake pads inspected by a professional to ensure they’re in good working condition. If you have a faulty or worn-out brake, make sure to replace the brake pad.
Brake Noise When Braking Slowly: Bottom Line
Now that you’re aware of the reasons behind the brake noise when braking slowly and how to fix it, we believe you’ll save yourself the frustration and stress next time this happens to you.
Just remember to give your car a regular check. And if you feel there’s any fault regarding your brake system, try to diagnose and fix the fault yourself. If you’re skeptical about the procedure, just head to the nearest auto repair shop and get the fix done.
Facts: Need-to-Know Knowledge about Brake Grinding
- Brake grinding is a sound that occurs when the caliper and brake disc come together while braking.
- There are three main situations that could cause brake grinding: pressing on the brakes, while driving, and sudden stops.
- The most likely cause of brake grinding is worn brake pads that have worn down to the metal backing plate underneath the pads.
- Brake pads usually come with a combination of graphite, metal, copper, and brass.
- Your brake rotors are the shiny discs against which the calipers squeeze to slow your vehicle and can rust or become contorted, causing squeaky brakes.
- A worn-out rotor will often make a piercing shriek felt through your steering column.
- Wheel bearings allow your tires to spin indefinitely without excessive heat, and a grinding noise may indicate a faulty wheel bearing.
- Low-quality brake pads may increase wear and tear on other brake parts and cause grinding or scraping noises.
- The braking system is complex and will require relubrication over time to prevent grinding noises caused by the caliper bolts.
- If your car has been idle for months, rust can be the source of your brake noise, and driving your vehicle at least once a month can help avoid most major problems.
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