OK - who's going to diagnose my problem?..(I think it's brake shoes).

[tref]

You'll jack it up, not find anything, put it down, and not hear it again for miles - CV joint!

 

[edh]

Collected the car from storage today, taking it to PH Sportscars for a little fettling tomorrow

As I was driving slowly through a car park I noticed a knock from the rear - seems to be transmitted through the body so you can feel it as well as hear it.
It's definitely rotational - I guess once for every wheel revolution.

I'm just about to jack the car up and have a look - so fire away with your guesses...

 

[Riverside]

If it's been sat on it's tyres for a while one or more could have gone out of round, but when I've had that it's shown up as a rhythmic humming at higher speeds (say 50+mph). Handbrake could be binding, or possibly a caliper piston but those would sound metallic. Frankly though I agree with Tref, CV joint (or drive shafts at least) is the most likely cause; give it a bit of a run & I guess it'll quieten down.

 

[zcacogp]

OR ... it could be a loose brake disk in the caliper. (I presume it's the S2 we're talking about here.) I had a caliper gate open on me once and the pad moved around making a noise pretty much identical to a duff CV joint. However given this is unlikely, I'll concur with Tref - CV joint! Oli.

 

[edh]

I'll have to find something more tricky next time... There's some play in the nearside driveshaft - I suppose the cv joints on that side suffer from the exhaust heat. I'm feeling lazy so I'll get ph to sort while it's there. Their labour rates make it an easier decision

 

[edh]

It's a lot quieter now... One other thing I suspected was something loose in the parking brake mechanism - there is a bit of a knock when you start to reverse. Anyway, I'll see what Rob thinks tomorrow

 

[944 man]

My guess would have been the parking brake. One of mine did something similar but only going backwards.

 

[T3rra]

Parking brack spring snapped or come free

 

[ChasR]

Parking brake retainer springs could be it. From memory they are around £6.50 each from Porsche. I would bank on getting two though. When mine went (it used to make strange noises (sometimes it would knock, at others it would squeal) the other spring went in a very short space of time. By that time I became a dab hand at changing them though!.

 

[edh]

Had another drive after getting the JMG steering shaft fitted at PH - Definitely parking brake related.... Will have to whip off the disks and have a look next week

 

[edh]

So is this it?

The end of the brake shoe is just coming away from the backplate I can't see anything else wrong with the brakes / hubs. ...and now I have 2 Porsches on stands with their rear calipers/ disks off - I was changing the (snapped) rear ARB on the Boxster & decided to treat the corrosion on the inner faces of the brake discs before it really takes hold. Bilt Hamber De-ox gel going on tonight..

 

[homesea]

I had the same sound it was the CV joints, sounded like that sketch from Monty Python with the coconuts for horses!

 

[edh]

Mine makes the noise when I pull on the handbrake when moving slow.