Scraping noise from front left wheel

[Shadgrind]

I have replaced the rotors and wheel bearings at the front and the scraping noise has continued. The backing plate is not bent and it increases with speed. It scrapes once every rotation of the wheel. I have absolutely no idea what it is. It hasn’t changed since I did the work on the vehicle. I am getting a bit fed up with this now.

Can someone please help I have put Rambo rotors on the car and Febi Bilstein rotors on, the pairings were correctly installed and I have no play in the wheel and the discs are brand-new.

 

[Shadgrind]

Oh, and by writers I mean discs as I am in the UK, I put rotors so that any American people reading this would understand as they use different terminology.

 

[Blobcat]

UK based forum so “Disks” is correct, our visitors from across the pond tend to come for solutions rather than provide resolutions.

I presume you mean “Brembo” discs… not sure how well John J would be at stopping cars… although I’m sure he’d manage it somehow.

I’d be jacking up the noisy side and spinning the wheel to see if you can see what’s causing it. Could be reluctor ring.

 

[Shadgrind]

Rambo rotors I was using dictation mode on my Mac, anyway, I have had the wheel off the ground jacked up on jackstands and it is as quiet as a mouse. No issues at all. But as soon as I go out on the road even very slowly safe, I have miles an hour, the noise starts. It sounds like the back plate is scraping on the disk. However it is not it is very clear from the disk.

The reason all this started was, I initially suspected the wheel bearings, which I changed. Also, the passenger side desk seemed to be walked as it was tight to turn the wheel once during a revolution so I have Brembo on the front of my car, they came with a coating on which I obviously left on it that grey look coating which you're not supposed to remove. I used copious quantities of brake clean.

I am at a loss, as I said it sounds like the back plate is rubbing against the disk, but it is not the disk is new the bearings are new, and yet the noise I had before all this started remains.

 

[KennyN]

No noise when wheel off the ground but noise when the weight of the car is on the ground ?

I would be checking / adjusting the wheel bearing.

K

 

[Shadgrind]

Its a new bearing and the sound and the fact that it was not reproducable when off the ground is exactly the same? Sorry if I appear difficult been working on cars since I was14 now 57 never had this before is it a Mercedes feature .
Its one scrape per revolution, sounds exctly like backing plate scraping.
To sum up its exactly the same noise as before:

The tyres are new, less than 1000 mile Goodyear asymetric F1's, they. were fine up to this
The bearings have been changed and adjusted, tightend up to fully seat and wound back to allow free movement
The discs have been changed
Checked backing plate for fouling issues

It doesn't sound very loud, you can bearly hear it once you are going over 50mph or if you ere listening to music.

 

[s5tuart]

Its a new bearing and the sound and the fact that it was not reproducable when off the ground is exactly the same? Sorry if I appear difficult been working on cars since I was14 now 57 never had this before is it a Mercedes feature .
Its one scrape per revolution, sounds exctly like backing plate scraping.
To sum up its exactly the same noise as before:

The tyres are new, less than 1000 mile Goodyear asymetric F1's, they. were fine up to this
The bearings have been changed and adjusted, tightend up to fully seat and wound back to allow free movement
The discs have been changed
Checked backing plate for fouling issues

It doesn't sound very loud, you can bearly hear it once you are going over 50mph or if you ere listening to music.

I don't suppose it's something as easy as a stone stuck behind the back plate is it?

 

[Shadgrind]

Well as I said, it makes no noise when I spin it but it isnt under load. Could be a good catch, I'm going to brave the cold, and miss the F1 before the rain starts and report back

 

[Shadgrind]

Oops, forgot to post after typing, doh! Anyway checked for stones could see clearly all around the disc, perfectly clear, went for a drive, still there! I now believe it is coming from somewhere behind the bulkhead/firewall it is still based on movement and increases with speed, sounds like the brake backing plate stone shield or whatever you want to call it, very similar to a backing plate scraping, quite quiet.

 

[Trev1964]

If it's per revolution, it must be wheel related.
Tyre on shock, back plate to disk, something along those lines.
I had same once on a BMW.
Used the wooden shaft of a hammer through the wheel spokes to push back late away from disc. Cured it.

You'd be surprised how much flexing a car does when moving.

 

[EmilysDad]

..... I have had the wheel off the ground jacked up on jackstands and ......

if you're in the UK then speak in English ....... you had the car on axle stands

 

[KennyN]

Use a black marker on the disc , inside / outside / outer diameter and move the vehicle slowly and see were it rubs clean.

Are the bearings one piece or taper rollers that need to be adjusted properly ?

K

 

[brandwooddixon]

I once had an issue where there was a scraping noise but only when the car was on full lock turning right. It turned out to be the backing plate, even though it was clear by at least 5mm or so there was obviously some play. I did tighten up the wheel bearing, but still needed to bend the back plate away to cure it.

I must ask though, are you certain that its from the front left wheel, have you sat in the passenger seat and have someone else drive the car slowly? Just asking as we all know how sounds can propagate oddly inside cars.