Grinding noise on med/hard braking.

Randell Floyd · 21 Jul 2015 at 15:58

Hi there guys.

I've a bit of a weird one.

A couple months ago I noticed on medium to hard braking the fsn brakes are making a very harsh grinding noise.

First think first checked for any stones stuck, nothing.

Then I began to notice that there where two separate rings on the brake discs that looked like there was something stuck in the pads causing a ring indentation.

Off came the pads, but nothing but smooth.

I though maybe a full break pads and disc change would sort it all out.

Having done a whole swap, the sound is still there, maybe even more so at a lower pressure of braking than before. There might even be a slight hint of ring indentation as mentioned above agin, but I've only taken her for a quick brake test so won't know for sure yet.

What's next to check/do? Would a calliper issue cause this? Some kind of rust on the hub etc?

Nasher · 21 Jul 2015 at 16:01

If it's only doing it while moving it has to be the discs or pads. Nothing else could cause it really. Could be metal is touching the disc at some point.

ZXSpectrum · 21 Jul 2015 at 16:04

Sounds like you have a seized piston in the calliper. Take the car out for a bit and test the brakes for a while and when you get home CAREFULLY look/touch the wheel and see if it is hot.

Randell Floyd · 21 Jul 2015 at 16:21

ZXSpectrum said:
Sounds like you have a seized piston in the calliper. Take the car out for a bit and test the brakes for a while and when you get home CAREFULLY look/touch the wheel and see if it is hot.

I tried it pre brake disc/pad change and there wasn't any real heat in the alloys, and having felt the sisters wheels when they baked due to a seized calliper they where very hot.

The pads had even wear, but the problems only been there a couple months so that wouldn't be a great tell to be honest.

I'm wondering how the seized calliper would present with noise, since this it isn't present in 90% of my driving, it's only present on say 70-100% pressure on the brakes. It also defiantly has a rotating grinding noise.

Plan of action so far it to take everything back off tomorrow and wire brush and brake clean it all and see if that reduces or removes the noise. Past that it's garage time :eek:

Randell Floyd · 21 Jul 2015 at 17:02

Here's a rough video of the sound, braking at 13 seconds in, that's a watered down example of the sound, it doesn't have the grinding sound to it on the video. (It almost sound like the previous cars drilled brake sound in the video tbh).

Shared via Amazon cloud so will need to link click sorry.

https://www.amazon.co.uk/clouddrive/share/tEk6YrVJWlt0I9NYswml77SLbHDcmoOS9JjcRuiFCJF?v=grid&ref_=cd_ph_share_link_copy

Rilot · 21 Jul 2015 at 17:19

Sounds like the brake heatshield rubbing against the disc or tyre. Could be a shot wheel bearing I guess. Does it do it when cornering in one direction?
It could also be something loose that rubs against the disc or driveshaft when braking. Ie it's loose, but not touching anything when normally moving but when breaking, the deceleration force causes it to move in contact with something that rotates.

Randell Floyd · 21 Jul 2015 at 17:33

Rilot said:
Sounds like the brake heatshield rubbing against the disc or tyre. Could be a shot wheel bearing I guess. Does it do it when cornering in one direction?
It could also be something loose that rubs against the disc or driveshaft when braking. Ie it's loose, but not touching anything when normally moving but when breaking, the deceleration force causes it to move in contact with something that rotates.

Nothing changes on cornering or straight line, it's the same.

I though about wheel bearing too but shouldn't there be some cornering noise too? Will check for play when jacked up tomorrow cleaning. Will also check for any parts that might be loose when moving cheers.

Kaeo · 21 Jul 2015 at 21:51

Get under it with a bar and or club hammer and make things move. Anything you can pull over near the brakes or wheel can be a culprit. Highly likely to be something around the caliper or disc touching it though. As Rilot says, my first thought was heatshield/dust cover.

Randell Floyd · 22 Jul 2015 at 13:50

Took everything off again this afternoon, cleaned everything that needed cleaning and put everything back.

No obvious play from the wheel when off the ground.

Had a quick drive, and not only is it still there, I would say it a smidge worse than before.

If I was a betting man I'd put 40% on wheel bearing 60% on a seized calliper, but none of the symptoms fit well.