Grinding Noise While Driving But Not When Brakes Applied – Why?

Have you ever been driving and heard a rough noise from your car, but then it stopped when you hit the brakes? It’s a confusing sound to try and diagnose, which happens to almost every car owner at some point. 

So, what could be causing the grinding noise while driving but not when brakes are applied? Well, a few things that often cause it include small rocks getting stuck in the brakes, issues with rusty rotors, stuck calipers, or a loose dust shield. 

The good news is there are usually simple fixes you can try, like cleaning out debris, lubing the rotors, or making a few brake adjustments. Let me tell you a little more about these causes and solutions.

Grinding Noise While Driving but Not When Brakes Applied – Six Causes and Solutions

Over the years, I’ve come across many different things that can cause grinding noise while driving that stops when you brake. Let me walk through six of the more common issues and what tends to fix them.

Stone Stuck Between Brake Shield and Rotor

When you’re driving, it’s easy for a little pebble or something to get wedged in between your brake shield and rotor. And when that happens, you’ll start hearing a grinding noise.

It’s pretty common actually, especially if you’re driving on gravel roads or places where stuff tends to get kicked up more easily. Those little rocks and acorns have a way of working their way right in there.

Leaving it for too long can do some damage to your brakes. But usually, you can just fix it yourself real quick. Just back up a bit and press the brakes a few times while you’re going in reverse. That’ll usually dislodge whatever’s stuck in there.

The best way to avoid it altogether is to try and stay on paved surfaces if you can. Dirt roads and rough terrain are just asking for stuff to get wedged in there.

And if you live on a gravel driveway or something, it’s probably going to happen more often, unfortunately.

Stuck Brake Caliper

The caliper is what squeezes the brake pads against the rotor to slow you down, but sometimes, it can get stuck in the “on” position. 

When this happens, your brakes will be partially applied all the time on that wheel, making that squealing or grinding noise. You might also notice the car pulling a bit to one side.

The caliper can seize up from rust or just not get used very often, like if the car sits for a long time. And driving like that isn’t good because it’s constantly making the pads rub on the rotor. It can overheat them and potentially start a fire if you’re not careful. 

Luckily, it’s usually not too hard to fix yourself. First, try jacking that side of the car up and spinning the wheel by hand. That might free it up.

If not, the slide pins that let the caliper move likely need cleaning and re-lubing with new grease. But if that, too, doesn’t fix it, you might have to replace the caliper or resurface the existing rotors. 

Rusty Brake Rotors

Over time, your brake rotors can start to get rusty underneath the brake pads. That’s pretty normal to see some surface rust buildup there. Often, you can just scrape it off and it’s usually not a big deal.

But if you let it sit for a while, the rust can eat into the metal and cause tiny pits in the rotor surface. Then, when you hit the brakes, it’ll make a grinding noise from the rust particles trapped between the pad and the rotor.

While lubing the rotors does fix it temporarily, the best way to prevent that is to drive your car regularly so the brakes get a chance to dry out between uses. Leaving it to sit for weeks at a time with moisture on the rotors is just asking for rust problems.

Parking indoors out of the rain and snow helps, too. And when you do take it out, give the brakes a few light presses to wipe off any rust before a long drive.

High-quality rotors also naturally resist rust a bit better over time, so consider investing in those as well.

Low-Quality Brake Pad or Rotor

When it’s time to replace your brake pads, you’ll find a pretty wide range of prices. Really cheap ones might seem like a good deal, but most often, you get what you pay for.

The super cheap pads can sometimes squeak or grind more because the material isn’t as good quality. And sometimes the expensive “top of the line” ones aren’t really worth the extra cost over mid-grade brands.

From what I’ve seen, the mid-range priced stuff is usually a pretty safe bet. You’re not wasting money but still getting brakes that’ll work well and last a good long time.

The same thing goes for rotors. Look for ones with rust protection coatings like zinc. That’ll keep them from corroding quickly like bare metal ones.

Also, don’t forget to read reviews online before buying. Other customers will explicitly tell you if certain brands are noisy or have problems. Saves a lot of frustration that way.

Loose Brake Dust Shield

Sometimes, the little cover around your brakes, known as the dust shield, can shake loose a bit. It’s supposed to keep dirt and dust from getting packed into the brakes.

But over time, with all the vibrations from driving, they’ll occasionally start rattling around a little. And when that happens, it can rub up against the brake rotor and squeal whenever you press the pedals. 

Luckily, it’s usually an easy fix. Just stick a flathead screwdriver up through the bottom and gently nudge the shield back into place. The trick is not pushing it too far, though, or it might start squeaking from being tweaked out of position.

And in the case of a loose or broken shroud that rattles against the rotor, you can use a zip tie to secure the shield to the knuckle before replacing the shroud. Here’s a video that might help:

Damaged or Caught in CV Joints

Constant velocity (CV) joints are what connect your drive wheels to the transmission, and let the wheels spin at different angles while you turn. If they get worn out over time, you’ll usually start hearing a grinding noise when cornering.

The sound tends to happen more when turning the steering wheel and gets louder the faster you go. It sounds almost like something is rubbing in there.

Nine times out of ten, a mechanic will be able to tell if the joints are just shot and need replacing. But I’ve also seen where a little rock or twig was wedged in there.

So, if you notice grinding, it can’t hurt to check the CV joints above carefully yourself first before assuming you need all new ones.

Seek Professional Help If You Can’t Fix It

If you’re investigating grinding noises under the hood and just can’t track down the problem, it’s totally fine to hand it over to someone who knows what they’re doing. 

The best thing to do at that point is to ask some people you trust for mechanic recommendations. Friends, family, coworkers – whoever keeps their cars running smoothly. Word of mouth is usually solid.

You can also check out reviews online. Places with years of happy customers that other people suggest tend to be safe bets.