Why are my brakes squeaking?
Unless you're driving a big rig with air brakes, your brakes are pretty quiet when they're doing their job. But sometimes our brakes get noisy to get our attention. They can squeal, grind, shudder or vibrate. When that happens, they are ready for maintenance! Let's take a look at a few of the typical ways brakes let us know they need some love and attention.
How do my brakes work?
The brakes on your car, truck or SUV come in one of two types — drum or disc. Drum brakes were the norm for many decades. But disc brakes do a better job of getting rid of the heat created in braking, and heat is the enemy of good braking. By the 1970s, disc brakes came into widespread use. The front brakes carry the bulk of the braking load and today, virtually all vehicles use disc brakes on the front. While most vehicles incorporate 4-wheel discs, meaning all four wheels have disc brakes, some manufacturers still use drum brakes for the rear.
Disc brakes operate similar to bicycle brakes. On a bicycle, the rubber pads that clamp onto the wheel are like the brake pads on a vehicle. The edge of the bike rim that the rubber pads grip is comparable to a car's rotor (also called a disc) which the brake pads clamp on to. And the bracket that the bike pads are mounted on serves the same function as the brake calipers on a vehicle.
The brakes in your vehicle depend on hydraulics to work. That means that when you press the brakes, brake fluid is pushed through the lines to the caliper. A small metal piston inside the caliper is then pushed out and closes the brake pads on either side of the rotor. The friction created by this clamping is what slows the vehicle. Drum brakes have more parts and older technology, but use the same basic principles. They use brake shoes rather than pads and brake drums in lieu of brake rotors, but the basic ideas are the same.
Why do brakes fail?
Brakes (typically) don't fail suddenly. It is more common that brakes wear out over time. Here are a few causes:
- The friction material on the pads or shoes wears down.
- The rotors are worn down from the friction of the pads.
- Although calipers don't “wear out” like pads and rotors, over time the pistons can “freeze” in their cylinders and they too will need replacement.
Those are the main brake parts you'll hear about, though a full brake inspection by your expertly-trained Ford service technician will always include the entire brake system.
Brake Noises and Warning Signs
As your brakes wear, sometimes they will give you a warning that something is wrong. Any time your vehicle starts making odd noises, you should get it checked. And if you suspect the noises are coming from your brakes, get it checked immediately!
Here are the typical noises and other warning signs you may experience when you apply the brakes:
- Grinding, squealing or clicking noises
- Soft or spongy brake pedal
- Pulsating, vibrating or “shuddering”
- Pulling to one side when braking
- Excessive drag
- Increased distance needed to stop
What do these noises mean?
The short answer is that there's a problem that should be checked out by your Ford dealer immediately! For more details, let's dig into each symptom and see what your vehicle is telling you.
If it sounds like metal-on-metal grinding or scraping, it usually means the friction material on the brake pads has worn away. In other words, there's not much braking material left. The brake pads need to be replaced immediately, and probably the rotors as well.
Disc Brakes are designed with a wear indicator to let you know when the pads are wearing dangerously thin. If the noise is a high-pitched squeal while driving that doesn't stop, this is likely the built-in wear indicator telling you it's time for new brake pads. (Though keep in mind some wear indicators are designed to sound-off only when the brakes are applied.) As the pads wear down and get thinner, the wear indicator — small metal tabs — contact and scrape the face of the brake rotor. It scrapes it like fingers on a chalkboard and is your vehicle's way of telling you to change the brake pads now!
Clicking noises usually happen if the clip that holds the pads in place breaks or comes loose.
Soft or spongy brake pedal usually means there's air in the brake system. This will cause the brakes to feel “mushy” or “soft” because unlike brake fluid, the air can be compressed and lets the pedal go further towards the floor. More importantly, the brakes are not being applied as they should be to slow down the car.
A pulsating or vibrating brake pedal usually means there are uneven spots on the rotors. This is usually caused by a build-up of friction material on the rotor. Keep in mind, a pulsating could also be caused by the antilock braking system (ABS) operating normally.
If your vehicle pulls to one side when you brake it usually means one of the front brake calipers has “hung up”. This means the piston isn't releasing and that brake is still engaged. Or, it could mean there's a brake fluid leak in one of the calipers. In either case, a caliper isn't doing its job and needs service right away.
If there's a sound like a pump running after braking, it may be the anti-lock braking system (ABS) pump. This is likely caused by one of the wheel speed sensors not working properly. This makes your vehicle's computer think one of the wheels is locked up. Speaking of ABS, if the ABS warning light on your dash lights up, that could be caused by a number of things, none of them good, so it's wise to get your vehicle checked out right away.
Drag when accelerating. This can mean the emergency brake is still “on”. This could be caused by corrosion on the emergency brake, leaving them engaged even after they've been released. Or, it could just be that the driver forgot to release the brake.
Longer than normal stopping distance likely means worn brake linings.
Normal Brake Pad Noises
All brake noises don't necessarily mean a brake job is in your immediate future. A few are normal. Sometimes brakes squeak after the vehicle has been sitting overnight, or in a humid area. Moisture can collect on the brake rotors, especially if it's humid. Or there could be surface rust on the rotors, caused by moisture, that is being scraped off by the brake pads. Usually this type of squeak disappears after applying the brakes a few times. If so, there's nothing to worry about.
Brake Jargon You Should Know:
These are terms and phrases you'll probably hear when talking about brakes with your Ford service advisor.
- Brake Fade is when the pedal is “mushy” or fades when braking. This typically occurs when the brakes have gotten so hot that the brake fluid begins to boil. When it boils it forms air bubbles. Unlike brake fluid, the air compresses allowing the brake pedal to become soft. Extended braking is usually the cause. One example of this would be driving down a winding mountain road towing a trailer and having to brake continuously on the way down.
- Warped Rotor is used to describe rotors when the problem is a brake shudder or vibration. Brake rotors don't actually warp but will wear unevenly. This can be caused by brake pad material being unevenly deposited on the face of the rotor. Uneven surface variation can lead to shudders and vibrations requiring brake service.
- Cutting, Turning, Machining or Resurfacing Rotors are phrases typically used to describe reconditioning a brake rotor surface. If the rotors have an uneven surface and are still thick enough, (as measured with a micrometer), they can be resurfaced using a brake lathe. This smoothes the rotor surface by cutting a very thin slice of metal from the surface to restore a uniform thickness.
Be a “Brake Whisperer”
As you have learned, there are quite a few sounds your brakes can make. A few may be normal, but most are warning signs that your brakes need service. We've talked mostly about brake pads (and shoes), rotors (and drums) and calipers, as these are the primary parts that routinely get serviced. Your Ford dealer will inspect the entire brake system including fluid levels and all of the related brake parts. Remember to listen to your vehicle and keep in mind what your brakes are telling you when they start making those unusual noises.
When it's time for brake service for your Ford, schedule an appointment with your local Ford dealer for trusted service, knowledge and expertise.