Worn out brake pads: Brake pads are a crucial part of your vehicle’s braking system. Properly functioning brakes are an essential safety feature for every vehicle. Brake pads do wear out and while your technical inspection officer will check your brake pads it is important that you, as a driver and a car owner, know how to recognize the early symptoms of bad brake pads. They should therefore be checked at regular intervals and replaced if necessary. If the brake pads are bad, this represents a high safety risk and also affects braking performance. Not to mention that driving around with bad brake pads can also destroy your otherwise good brake discs.
We think that the reasons above are more than good enough that you should continue reading. Here are the most common symptoms of worn out brake pads.
How do I know if my brake pads are bad?
Modern or well, younger vehicles will usually come with electronic wear indicators. This simple indicator will trigger a warning light or warning message on your dashboard once the thickness of the brake pad lining gets under the minimal value (usually 4mm). However, if you drive an older car, you will have to use your ears, eyes and other senses.
You can visually inspect the thickness of brake pads if you turn your wheel completely to the left or right. This will allow you to get a better view of the brake discs, calipers and brake pads. If you see there is very little “meat” or friction lining on the brake pads, you should visit a mechanic to confirm your diagnosis. Another good time to inspect brake pads is when you are rotating your wheels or when you are switching between summer and winter tires. When you remove the wheels, you have a clear view of the brake system. Inspect the brake pads, take pictures and get someone else’s opinion if you suspect that your brake pads are worn out.
There should be at least 4 mm (almost ¼ inch) of lining on the brake bad. Anything less than that is considered dangerous and you should have your brake pads replaced. If your vehicle has drum brakes, the minimum thickness of brake pads should not be lower than 1 mm.
Bad brake pads will also signal trouble through many of the symptoms of worn-out brake pads that we will cover as we continue.
Symptoms of bad brake pads (And reasons for those symptoms)
Most other websites will list the 5 generic symptoms of bad brake pads like grinding noises, squeaking noises, bad braking performance, etc… What we want to do is introduce symptoms and although we will be repeating some of those symptoms it is because there are different causes for those symptoms. Sometimes even fairly new brake pads can be causing trouble, even though most drivers think it is impossible since they are new. Symptoms of worn out brake pads are in some ways also similar to symptoms of bad wheel bearings.
Grinding noises when you are not braking
If your brake pads are old but not necessarily worn out, what can happen is that the friction material that comes into contact with the brake disc actually detaches from the carrier plate of the brake pad. This detachment of the friction lining can also happen if brake pads are of poor quality if they are poorly fitted or because of rusting between the carrier plate and the friction material.
When this happens, you will often experience grinding noises even when you are not braking as the detached friction material freely grinds upon the brake discs. Other symptoms of this can include squeaking when braking, lessened braking performance, and overheating of the braking system.
Weird noises and poor braking performance
Weird noises and poor braking performance on brake pads that have enough friction material are usually a consequence of overheating. Overheating can happen if your brake caliper/brake pistons get stuck and do not move back from the brake disc. It can also happen during extreme driving conditions (excessive braking when going downhill for instance) and during continuous braking (brake pads have no time to cool off).
Overheating disintegrates the friction material and lining, it makes the surface of the brake pad “glassy” and porous. All of this leads to poor braking performance which is usually accompanied with weird noises and sounds.
Poor braking performance with new brake pads and weird noises
If you just installed new brake pads but ignored the fact that you also have worn out brake discs, this one is for you. Just kidding, this can also happen if foreign objects come in between the brake pad and the brake disc. In some cases, this can also be caused by salt and dirt deposits on brake discs or brake pads during winter. Worn out brake discs or rotors can damage the surface of the brake pad, causing bad braking performance and weird noises. Damaged brake pads will need replacement.
Weird noises accompanied by poor braking performance and premature wear of brake pads
Another set of reasons for weird noises, poor braking performance and premature wear of the brake pads is oftentimes incorrect assembly, mechanical overstressing and overheating, bad quality or use of non-compliant brake pads. Friction lining can also start chipping away which causes additional problems. Make sure you always buy high-quality brake pads that are the right fit for your vehicle. The price difference between cheap and high-quality brake pads is not something you should really pay attention to. The price difference is small, and brake pads represent one of the more important safety components of your vehicle. Don’t save pennies where you absolutely should not.
Loud, metal grinding noises when braking and poor brake performance
Metal grinding noises and insanely bad braking performance can only be caused by one thing; completely worn out brake pads. When this happens, your brake pads essentially have no more “meat” on them, the friction material is completely gone and you are lucky enough to have some braking effect when pressing the brake pedal. The thing that is bringing you to a stop is a direct contact between the back, the carrier plate of the brake pad that comes in contact with the brake disc. Doing this will also destroy your brake discs.
Uneven braking, the car pulls to the side when braking
If your car tends to pull to one side when braking it is usually a sign of uneven brake pad wear. Brake pads on one side of the wheel are likely more worn out than on the other side. This is caused by stiff brake pistons or stuck/jammed guide bolts on the brake caliper. The side that is being used more, is also prone to overheating and premature wear.
Squeaking noises and poor braking performance on one side
New brake pads have a so-called “run in” phase. During this phase, you should not overheat and overstress the brake pads in order to avoid damage. If you fail to do so, the friction material of the brake pads will get weird glazing which causes squeaking noises when braking and a loss of braking effect.
If the damage has been done, you can still save the new brake pads by evenly grinding off the friction material.
Noises when braking accompanied by uneven braking performance
Yes, there is yet another potential reason why your brake pads might be making weird sounds and have lessened braking performance. Your brake pads might be contaminated by grease, oil or other substances that prevent proper braking. This might happen if your mechanic is clumsy and he accidentally spills oil on the brake pads (which happens more often than you would think), you could have a defective driveshaft boot or a leaky braking system. Any contaminants on the brake pad lower the brake effect and if the contamination is one-sided, it can also lead to uneven braking which means your car will pull to one side of the road.
Vibrating brake pedal
If your brake pedal is vibrating there is a big chance that something is wrong with your brake pads. The vibration of the brake pedal can be caused by overheated brake pedals that developed the previously mentioned “glazing” or brake pads where the friction material has glued off the metal carrier plate. There can be
Clicking and rattling noises coming from the brake pads
Clicking and metallic rattling noises usually indicate that your brake pad is wobbling. All brake pads have a certain mechanism that keeps them in place. They are held in place with pins, clips or even bolts. If the mechanism unlatches, the entire brake pad can start wobbling and causing all sorts of noises. The clicking sound usually eases off as you push the brake pedal and it presses the wobbling brake pad against the brake disc.
Frequently Asked Questions
Are Worn Brake Pads Dangerous?
Yes, driving with worn out brake pads is incredibly dangerous. Bad brake pads significantly reduce your stopping distance and the overall feel and performance of your brakes.
Is Brake Pad Dust Dangerous?
In terms of impact on health, yes, brake pad dust is essentially particles of friction materials that rub against the surface of a brake disc. A certain amount of those dust particles go into the air and we breathe in some of it. Research has shown that it increases the chances for inflammation of the lungs and it reduces immunity.
How do Bad Brake Pads Sound Like?
A bad brake pad can cause several weird sounds. There can be metallic grinding, rattling, clicking sounds when you release the brake pedal, squeaking noise when you press the brake pedal and so on.
What Are The Signs Of Bad Brake Pads?
Common signs of bad brakes include:
- Weird noises and sounds
- Uneven braking (car pulls to the side)
- Reduced braking performance
- Vibrating brake pedal
Can Brake Pads Be Put On Wrong?
Yes, brake pads can be put on wrong. Professional assembly is recommended in order to assure optimal performance and safety on the road. Wrongful assembly can also lead to premature failure and wear of brake pads.
How Long Do Brake Pads Take To Bed or Break-In?
To break in your new brake pads and resin in the friction material of a brake pad, use the 30-30-30 principle and take it easy for the first few miles. The 30-30-30 principle requires 30 slow stops from 30 mph (50 kph) and a resting period of 30 seconds in between each stop so your brakes cool off. Your mechanic should execute the 30-30-30 principle in most cases but we still recommend taking it easy with your new brake pads on the first few rides.
How Long Do Brake Pads Last?
The lifespan of brake pads is heavily connected to the way you drive, the weight of your car and the terrain you drive on. Generally speaking, a brake pad should last anywhere from 20,000 to 60,000 miles or 30,000 to 90,000 kilometers.
As you have learned by now, symptoms of worn out brake pads can have several reasons behind them. Now that you know them, diagnosing your issues can be much easier and if you are lucky, a replacement is not yet needed. But in any case, replacing bad brake pads is not a cost that will heavily affect your bank balance. Seeing as you will not be replacing bad brake pads every month, make sure you do not buy cheap brake pads. Choose quality over everything when it comes to brake pads, they are an essential part for your safety on the road.