A grinding noise when you brake usually means the brake pads have worn down to the metal backing, and that metal is now rubbing on the disc. Treat it as urgent: book in straight away, and if it's a harsh metal-on-metal grind every time you brake, stop driving and call us.
There are a couple of less serious causes too. Here's how to tell them apart.
What causes brakes to grind?
From most to least worrying:
- Pads worn through. Once the friction material is gone, the steel backing plate grinds on the disc. You hear it, and often feel it through the pedal. The car stops less well, and the disc gets scored with every stop.
- A stone or bit of grit caught in the brake. A small stone can get trapped between the disc and the thin metal shield behind it. It makes a scraping or grinding noise that can come and go, sometimes even when you're not braking. Annoying, usually harmless once it's out, but it can scratch the disc if left.
- Rust after the car has sat. Leave a car parked for a week or two, especially through a damp North Shore winter, and the discs get a layer of surface rust. The first few stops grind or scrape, then it clears. If it's gone after a few stops, that's normal.
- A sticking calliper. The calliper is the clamp that pushes the pad onto the disc. If it doesn't let go properly, the pad keeps dragging. You might notice a grinding or rubbing noise, a hot smell after driving, or the car pulling to one side.
- Worn discs. Discs wear too. A disc with a deep lip or grooves can make the brakes grind or feel rough even with newer pads.
Squealing usually comes first. Many pads have a small metal tab that squeals when the pad is nearly worn, as a warning. Grinding is often what you get when that squeal has been ignored for a while. We've written about why brakes squeal too.
Is it actually the brakes?
Worth a quick check. Note when you hear it:
- Only when you press the brake pedal: almost always brakes.
- All the time, louder with speed, and it changes as you turn: more likely a wheel bearing than the brakes.
- A buzzing or juddering through the pedal when you brake hard or on gravel: that can be the ABS (anti-lock brakes) doing its job, and it's normal in a hard stop.
If you're not sure, tell us what you hear and when. Cold or warm, slow or fast, turning or straight. That narrows it down before we've lifted the car.
When should I stop driving?
Stop driving and call us if:
- the grind is harsh and metallic, and happens every time you brake
- the pedal feels soft, sinks further than usual, or the car takes longer to stop
- the car pulls hard to one side when you brake
- the brake warning light is on
Book in this week if the grinding is light, comes and goes, or only happens on the first stops of the day and then clears for good.
The longer worn-through pads are left, the more damage they do. What could have been new pads often becomes new pads and discs, because the disc gets scored too deep to keep. If the car also shudders when you brake, that points to the discs as well: Why does my car shake when I brake?
What happens when you bring it in?
We take the wheels off and look at the pads, discs, callipers and the brake hardware. You get a plain answer: what's making the noise, what needs doing now, and what can wait. The price is agreed before any work starts, and nothing extra is done without your OK in writing.
Quick questions
Can I drive to the workshop with grinding brakes?
If the brakes still stop the car normally, it isn't a harsh metal grind on every stop, and it's a short trip, drive gently and leave plenty of room. If the pedal feels wrong or the car pulls, don't. Call us and we'll talk through the best way to get it here.
Do I always need new discs if the brakes grind?
Not always. It depends how deep the damage goes. We measure the discs and tell you what we find before anything is done.
Will grinding brakes fail a WOF?
They can. The WOF checks how the brakes perform and their condition, and pads worn to the metal or badly damaged discs can fail.
Brake repairs in Albany and the North Shore
Midas Albany is at 3C Saturn Place, Albany. Family owned since 2004, MTA Assured, and the price is agreed before any work starts. Not sure what the noise is? Our $89 diagnostic finds it, and it's credited against the repair if we do it.
See our brake repairs and diagnostics.
Call Robin on 09 415 6595, book online, or request a callback. Monday to Friday 7:30am to 4:30pm, Saturday 8am to 12pm.
Written by the Midas Albany team.