DDK - Die Deutschen Klassiker

Hi,

Looking for a little expert help with a mysterious and increasingly frustrating noise from my 1968 912

Its an intermittent droning/whining sound, usually happens over 40mph. It it is at its worst when taking long corners, developing into a high-pitched whine with a little vibration. Dab the brakes and it disappears (but returns as soon as you release the pedal). Seems to only happen when the car is warm.

Thought is sounded like wheel bearings so replaced front and rear. We cleaned the brakes and replaced the squeel shims. The noise went away, only to return after 10 miles. I've ordered new diff bearings. After that I'm at a loss.

Any ideas/clues gratefully received.

Cheers
Neil

is the noise from the front or rear?

left or right hand corners? Does accelerating or decellerating make a difference?

shed7 wrote:Its an intermittent droning/whining sound, usually happens over 40mph.

I presume you've checked that the wife's not in the passenger seat?

Whose wife?

when it does it - check to see if any of the wheels are hot - could be a sticky caliper

With Ian on this one, it sounds like a pad humming against the disc. If the pads have worn with a slight taper this can set them off. Try filing a 45deg chamfer on the front and rear edges of the pad.

Thanks all - will check out the brakes

Have checked wife. Different pitch so safe there