Five Common Brake Problems in Cars
Five Most Common Brake Problems
Brake problems can be daunting if you don't know what's causing them. Fear of the unknown causes anxiety. You have questions like: Will my brakes fail? Are they safe? Can I drive my car? Should I drive my car?
Here are five of the most common brake problems I run into, starting with the most serious. It's good to understand what the cause of your problem might be, before a mechanic starts talking about the need to replace this or that. If you don’t find your issue here, look also at my article on brake noises, look through the comments at the end, or leave a comment yourself telling your story.
- Soft brake pedal
- Car pulls to one side
- Steering wheel shakes when brakes are applied
- Brake pedal pulses up and down
- Whole car shakes when brakes are applied
Parts of the Brake System
In case these terms are new to you, real quick, I'll tell you that to stop the car, the master cylinder sends out fluid through tubes under pressure to drive a pincher (a “caliper”) that presses a “pad” or “shoe” against a metal disc (“rotor”) or drum. Most modern brakes have rotors; older ones have drums, especially in the rear.
1. Soft Brake Pedal
A soft brake pedal is a MAJOR brake issue. If your brake pedal feels squishy, "like stepping on a plum," and won't stop on the way down unless you pump it, or the brake pedal sinks to the floor with little or no resistance, you have a dangerous situation and should NOT drive any further! If you do, it could be a matter of minutes until you smash into something.
When the brake pedal gets soft or sinks to the floor, it's generally due to a leak in the braking system, most commonly the master cylinder leaking internally or externally.
The first thing you should do is check your brake fluid--look in your owner's manual to see how.
A master cylinder may fail in two ways: internally or externally. If the brake fluid reservoir is full and there are no signs of leaks, the problem is usually an internal problem that you can’t identify just by looking at the master cylinder. Don't drive the car in any case; there is something wrong with your brakes if the pedal is soft.
It's worth grabbing a flashlight and looking to see whether the master cylinder is leaking visibly. If it is, you should be able see the fluid on the carpet under your dash, just over your brake pedal. The pictures below show the master cylinder under the brake pedal.
Location of the Master Cylinder
The only fix I recommend for a faulty master cylinder is to replace it with a new one. You shouldn't waste your valuable time trying to rebuild it. It's a vital component in your car; leave it to the pros. You wouldn’t pack your own parachute on your first jump, would you?
2. Car Pulls to One Side When Braking
A car that pulls to one side can be annoying and also dangerous. This braking problem can caused by several different things, even the tires (see below), but the most common cause is a frozen caliper. Over time, a caliper can freeze up gradually, a process that can go unnoticed for a long period of time.
One way a caliper can freeze up is by the piston on the caliper being stuck in its bore. If the dust boot that protects the piston from the elements gets torn, water and debris will penetrate the metal in the caliper and cause rust and corrosion. If the piston is stuck, and the fluid pressure can't push it back into the bore easily, the pressure on the pads will be uneven and the car will pull. To fix this problem you will need to replace the caliper.
Another possibility is that the pistons got bent, during a brake job or a car accident, and can't move freely any more, causing the caliper to bind and limiting the amount of pressure to the pads.
The caliper can also freeze up if the caliper slide pins have lost lubrication because they have not been maintained properly. If the slide pins are your problem, they need to be cleaned and lubricated or replaced. You can buy an overhaul kit for calipers, but they are hard to find and your caliper may not be worth bringing back to life. Buying a new caliper may cost more but you will make up the cost with the time you save. Been there, done that!
Other Causes of a Pull to One Side When Braking
A faulty proportioning valve or master cylinder could also cause a pull to one side when braking; this is unusual but it does happen. Most braking systems work on a diagonal braking design for safety reasons; that is, the left front and right rear brakes work together and so do the right front and left rear. That way, if there is a leak in one part of the system, it should only affect one front brake and one rear brake. If this is what is going on, you need to identify and replace the faulty part.
A pull when braking may also have nothing to do with brakes. Bad front tires, or broken belts in a front tire, could cause it. Any pull caused by unevenly worn tires will be amplified when you step on the brakes. The tires' contact surfaces expand when you brake, thus putting more pressure on the bad tire and causing the pull to worsen. Replacing your tires will fix this, or you could try rotating your front tires to the rear of the vehicle.
3. Steering Wheel Shakes When Brakes Are Applied
This is a very common brake issue on all makes and models: when you’re driving at highway speeds and you apply your brakes, the steering wheel shakes.
There are many possible causes of this shaking, including the front rotors being warped, hot spots (slight irregularities) on your rotors caused by excessive heat, or pad impressions. If your car sits for long periods without moving, moisture from rain or high humidity causes your rotors to rust, except for the patch of rotor surface where the pads rest. This patch of uneven rotor surface is called a pad impression and will cause the brakes to pulsate.
This brake pulsation can be fixed very easily by having your rotors resurfaced (which is cheaper) or replaced (more expensive). You can resurface the rotors if they are still thick enough. Every rotor has a "minimum spec" for thickness, usually stamped on the rotor near the hub where the lug nuts are. The rotor needs to be measured at the thinnest point with a micrometer or vernier caliper to determine whether it can be resurfaced or not.
Steering Wheel Vibration When Braking
An intermittent noise when braking lightly, as in the video below, could also be related to an uneven surface on the rotors.
4. Brake Pedal Pulses Up and Down When Applying Brakes
If every time you apply your brakes, your brake pedal pulses up and down, the problem is usually caused by the rotors being warped or out of true. As rotors age, they go through the heating and cooling process thousands of times, so it's inevitable for them to lose their shape or trueness. If you do a lot of highway driving and you happen to be hard on your brakes, you will probably run into this problem many times in the life of your car.
The fix for this brake problem is simple: resurfacing the rotors, if they are still thick enough (see section 3 above), or replacing them if they are not. If you do either of these processes, and your brake pads are more than half worn, it’s worth it to just replace the pads at the same time for the peace of mind it will give you; pads wear out frequently (they are a consumable item) and you might as well deal with them while in the neighborhood.
EBC makes quality brake pads that don't make much noise.
A Scraping Noise After a Brake Job May Be Easy to Fix
5. Whole Car Shakes When Brakes Are Applied
If your whole car shakes when your brakes are applied, it could be just your rear brakes. As a rule of thumb, shaking caused by a problem in the front end of the car will be felt in the steering wheel, while shaking in the rear will seem to affect the whole car.
To determine if your rear brakes are the problem, you need to test them in isolation. One way to test your rear drum brakes is to apply the parking brake slightly while driving, because the parking brake uses the drum brakes in the rear. You can do this test if your emergency brake handle is near the center console and it is the style that you pull up with your hand. Note: I don’t recommend pulling up on the emergency brake handle at high speeds, it can cause your rear brakes to lock up and send the vehicle into a spin causing death or serious injury!
To do this test, drive your car in a remote location with no traffic at a speed of about 30 miles an hour. Push and hold the release button on the end of the emergency brake handle; this is so the emergency brake does not lock into place and can be released easily. Meanwhile, pull up on the handle just enough to feel the rear brakes grab slightly. If your rear drums are the cause of the brake pulsation, you will feel the pulsation at this time, and the car will shake when the emergency brake is applied.
If this is your problem, then the fix is to resurface the rear drums or replace them. Again, you will have to measure the drums to determine if they can be resurfaced or not.
If you have rear disc brakes, this procedure may not work because some makes and models have a separate emergency brake, which is connected not to the rear rotor and caliper, but to a special drum inside the rear rotors with a separate braking system. If you have this type of rear braking system, it is almost impossible to isolate the rear brakes.
Hopefully this information will help you (and your mechanic) decide where to start when fixing your problem. When you are in a crisis situation like a brake problem, some mechanics will take advantage of the customer and over-sell the work that really needs to be done. There are only about nine evil mechanics in the world, they just move around a lot!
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More on Brakes by Eddie Carrara
- How to Replace Honda Brake Pads: Tips and Precautions. Avoid making costly mistakes when replacing your brake pads on your Honda. Brake jobs seem easy enough, remove a couple of bolts, spray some cleaner, and replace the worn-out pads, right? I will explain some important steps.
- Brake Noises: What Causes Them and How to Fix Them. Three common brake noises I encounter every day: a grinding sound, a thumping from the rear, and a squeak.
- Four Common Brake Squeaks. If your brakes squeak, and you want to know why, maybe I can help! Here are four common brake squeaks plus a bonus scraping noise; compare these situations to yours. Questions are welcome.
Questions & Answers
A year and a half ago (from 78,000 to 88,000 miles), I had the whole brake system replaced, i.e., pad, rotor, and lines. The mechanic is now telling me I need all of those parts replace again. Is this possible?