Scraping / rubbing noise when coasting

[They_all_do_that_sir]

Apologies as this is for the focus (2001, 1.6 pez) but figured I'd get more attention in here.

 

This is driving me bonkers

 

When coasting there is a loud rubbing or scraping noise from the near side front. When you apply power it goes away. It is still there under braking and with the clutch depressed.

 

Driving slowly with full right lock the noise is extremely loud, full left lock it's not there.

 

Last night I jacked the car up and couldn't replicate the noise by spinning the wheel.

 

I removed the wheel, the front disc was loose and I could replicate the noise by pulling at the disc. I put the wheel nuts on without the wheel and tightened them up, could no longer replicate the noise.

 

Put wheel back on and went for a drive and it's as bad as ever......

 

It had a new wheel bearing, lower arm and drop link on that side for the MOT a few months ago and hasn't done too many miles since

 

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[mrbenn]

Did the pads look ok? Almost sounds like a brake pad breaking up or metal wear indicator bent, or perhaps a build up of rust on one of the edges of the disc in the hub area.

[The Moog]

Brake backplate?

 

Or the one I had was the ball joint had a piece of metal to protect it which was rubbing. I cut the offending bit off.

[spike60]

+1 for backplate, AFAIK you can get shot of them without MOT probs unless they have have handbrake shoes etc mounted on them if rear.. My BMW 530 has had 1 then 2 missing for 3 years because thay would touch the disc. Also on BMW I've had a build up of rust on the inner edge of the inner disc face intermittently touching the backplate.

[bramz7]

Yeah my recently acquired 406 is doing this every so often, generally coming down a mild incline. My feeling was also the backing plate.

My Tipo also does it, but apparently the front discs are getting to the point of needing replacement.

[twosmoke300]

Rust build up on caliper carrier touching on disc when wheel nuts fully tightened?

[HMC]

Driveshaft/cv issue? Only under the power is the assembly is being loaded with torque which might limit play/movement that is generating the noise, also rears its head on full lock which fits with something cv related.

[Asimo]

Is there a support bearing on the driveshaft, between gearbox and the inner CV joint?

These bearings are rubber mounted and I gather get noisy quite often on Fords.

(Similar problem occurs on Transit Connect which os how I became aware of the issue)

Noise would be torque related and steering angle related as the driveshaft "leans" on this bearing as these change.

[sierraman]

There isn’t a back plate on the front brakes?

 

My thoughts would be a wheel bearing or a CV joint. Difficult to say without actually seeing it. Sometimes you need to have the suspension under load to accurately test stuff like this as like it is on the shaker for the test.

[MikeR]

 the support bearing is on the off side on this car , I would have a look at the back of the bearing carrier , split ABS ring ( prob not fitted ) , duff gaiter clamp etc , or even swap the tyre !!!

[They_all_do_that_sir]

Cheers for the pointers chaps. It can wait till tomorrow as it's now dark and cold.

 

No backing plates, and as said the support bracket is on the other side.

 

It had a new lower arm (inc ball joint) and new wheel bearing not that long ago.

 

I had to take it a short run earlier, above 40mph it doesn't make any noise. Slowing makes the noise louder and louder until walking pace where it is a very loud RUUUUB......RUUUUB

 

Pushing the car hard into a roundabout probably isn't a great idea when you suspect a fault but even flinging a lot of weight onto that wheel doesn't produce any noise unless you lift off the accelerator.......

 

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[DSdriver]

I had some disc pads contaminated with tool steel in the friction material. 

[MikeR]

I lay odds on the tyre ,,,, but here is a picture to study by the fire !

 

[They_all_do_that_sir]

  On 17/11/2017 at 19:53, MikeR said:

I lay odds on the tyre ,,,, but here is a picture to study by the fire !

 

20170901_135626.jpg

Funny the front tyres are almost completely buggered. They are winter tyres too and *just* road legal, I'm nursing them till payday!

 

Might swap the front tyres and see if the noise travels.....

 

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[dieselassist]

have you looked at the calipers; ie- might be a caliper sticking on; my brother's focus had the sympthoms described above; it eventually got so bad smoke was emitting from the front passenger corner, n it became a right stubborn mule to drive - I gave him a lend of a lump hammer to carry round to pullover n bash the caliper through the gaps in the 5 spoke rims, till he had the coin to replace it with a salvage caliper....

[twosmoke300]

Hammers don't fix calipers !

[dollywobbler]

Had a horrible brake noise on my XM. Turns out I'd forgotten to fit the retaining screw to the disc. The wheel bolts alone were not sufficient to remove every bit of play from the disc.

[They_all_do_that_sir]

  On 17/11/2017 at 21:47, dollywobbler said:

Had a horrible brake noise on my XM. Turns out I'd forgotten to fit the retaining screw to the disc. The wheel bolts alone were not sufficient to remove every bit of play from the disc.

Unfortunately the focus doesn't use retaining screws

 

As part of tomorrow's activities I'll be cleaning the hub behind the disc to ensure it's sitting as flush as possible

 

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[sierraman]

The retaining screw won’t make a blind bit of difference.

[twosmoke300]

Was just gonna say that . If you rely on an m6 csk screw to secure you disc you are in trouble . My guess was it had the wrong combo of flat faced or cone nuts and steel / alloy wheels

[MikeR]

whilst we a have a petrol Focus under discussion , would it cause problems to put a hidden switch in series with the fuel cut off thingy in the drivers well ?

[They_all_do_that_sir]

Afternoon chaps, time for an update

 

Stripped off caliper and disc. Cleaned them up, and gave the caliper carrier a good tidy as well.

 

Pads have plenty of life and no obvious damage. Disc is probably borderline.

 

Both mating surfaces clean as a whistle then put disc back on.

 

Everything back together and went for a drive - no noise!!! Yay!!

 

But what's This? Awk crap it's a very faint scrape....scrape....scrape sound starting up again.

 

It's still mega faint but I'll take it a proper run later and see if the noise returns.

 

Noticed when rotating the disc with the wheel off there is a sticky point.....I had ruled out the possibility of a warped disc as there's no vibration under braking and applying the brakes made no difference to the noise

 

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[MikeR]

where the pads a sloppy fit in the carrier ?  , I always make sure mine can float a little bit  so they dont stick ...

[They_all_do_that_sir]

  On 18/11/2017 at 13:26, MikeR said:

where the pads a sloppy fit in the carrier ? , I always make sure mine can float a little bit so they dont stick ...

They do have a bit of float in the carrier but they are tight to the disc once everything is back on

 

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