Bit of help needed please!

I have what can only be described as the noise from hell developed on my Scoob. It is not engine related, it is not transmission related (as I can free-wheel downhill and the noise continues to increase in shrillness, not volume, with speed), and apparently it is not wheel-bearing related, as those have been checked, there is no play, and they are not getting hot. The brakes were checked over at the last service only 2k ago.

The only change I have made recently is a new set of Kumho tyres. I have even had a 4 wheel alignment done which, if anything, has increased the intensity of the noise!

I am at the end of my tether trying to trace this. I am contemplating having to wear ear plugs. Is it really possible that the tyres are making a noise which starts as low drone at low speed and then moves up the range to a harsh shrill scream? Aaaaaaaargh…

Thanks all.

 

I had similar problem last year and it turned out to be the dust cover on the discs was bent and touching the disc..

 

Stone trapped in the braking system somewhere?

 

Either of the two above: stones get between the rear disc protector and the disc and the noise is appalling

 

You, sir, may be onto something no-one else has noticed (including me). One of the discs is ridged. The others are smooth. The caliper was only rebuilt recently, but there may be something in there. Cheers.

 

It's the front disc that is scored, but I'll have them all looked at. Cheers.

 

No mate, the protector on the REAR of the disc, not the rear-disc. They all have 'em from new, mine now has none

 

Sorry mate, didn't read it right. I have aftermarket discs though, from Aztec. The grooved, not drilled ones. I'll have a good look at it. Cheers.

 

Brakes have now had a good going over, as have the wheels generally, wheel bearings, etc. It's not any of them. Beginning to think it sounds like a front/rear differential problem. The noise builds with speed. How expensive if this is the problem?

Cheers,