Any suggestions please - grating noise

[DPS20K]

I've got a grating noise coming from the rear left hand side. It only happens under breaking and then only after the car has been driven for 15 miles or so, not when it is cold. It sounds like a stone rubbing on the disc but it's not. I have just fitted new discs, pads and handbrake shoes all round and the noise was there before and is exactly the same afterwards.
I've checked everything I can see and there is no sign of rubbing anywhere.
Could it possibly be a wheel bearing on the way out? Any other suggestions?

 

[2b1ask1]

How are your tie rods, anti-roll bar bushes and drop links?

Tie rod play you notice under hard acceleration when it feels like it wants to change lanes every gear change!

 

[Zep]

Wheel bearing do get worse when hot (at least mine did) so it's possible. Do you think it might be quiet enough to be masked by engine noise when you are on the loud pedal?

If it helps, my wheel bearing appeared to have no movement but was a little noisy until the hub nut was undone on the drive shaft which removed the clamping force. After that it was like stirring a bucket of gravel, which explained the noise.

 

[RW3200]

Did you check the brake calliper, could it be a sticking piston?
As it starts when you brake it could be the calliper isn't releasing properly when you come off the brake.

 

[DPS20K]

Pistons were all checked and tie bars were done at last service. It's definitely only under braking. I've flicked it into neutral and coasted - no noise until I hit the brakes then noise stops as soon as I come off the pedal. The noise is also directly related to wheel speed. I gave everything on the brakes a really good clean and checked it all over so I don't think it's directly brake related. The noise is exactly the same as it was before I changed everything.

 

[wink]

If it only happens when you're braking it's got to be directly brake related. Sticking pad or piston is my bet.

 

[2b1ask1]

May be worth doing a handbrake road service, find a quiet stretch and rolling along at about 20 mph pull the handbrake on firmly till you feel it dragging for about five to ten seconds and release, give it a minute to disperse heat and repeat three or four times, it settles the shoes and beds them in as well as polishing them up a bit.

It should rule out the handbrake as your issue at least.

 

[StuartW]

Yep, calipers is where I would look first - they can be a bit sticky

 

[DPS20K]

Yep, calipers is where I would look first - they can be a bit sticky

But wouldn't stick calipers result in the noise when not braking because the pad is not retracting, rather than a noise when braking? I'm certain it isn't the calipers anyway because I checked them when fitting the new brake pads. I'm still certain it is nothing to do with the brake pads, discs or calipers, or the handbrake. The discs were replaced, new pads, new handbrake shoes, new handbrake cable, calipers thoroughly cleaned and the noise is exactly the same as it was before I changed anything. The only thing I noticed when doing it was that the wheel bearing on that side was slightly tighter than on the other side. There was no play but it just didn't turn as freely. Oh well, another job for Emblem in a couple of weeks when it has it's service.

 

[daverichardson]

In my recent MOT the rear calipers needed easing as they were tending to stick
Worth a try