Mooing front end!

[944Fripp]

I have a re-occurring issue with my S2. It sounds as if I have a dragging calliper and I can feel it through the steering wheel up to about 20mph when traveling straight. The sound goes away as soon as I apply the brakes. The sound is like a mooing sound which comes and goes.

I have had the brakes looked at, dismantled and put back together and they did indeed find a dragging calliper. They were fine for about a week, then it came back! Do I need a new hub or something like that?! It doesn't really make sense.

I also get a similar sound and feel when I dry steer (when parking for example) or have the wheel turned and go slowly round a corner but I think this could be a worn out power steering pump so don't think they are related. Incidentally, any idea of the cost to repair or replace this?

Thanks in advance!

 

[DivineE]

Hmmm I would think your looking at two totally different faults but they shouldn't sound too similar. The mooing sound when dry steering will be the power steering pump dragging air through the system. It'll be leaking from the hoses under the brown power steering fluid tank most likely but topping it up and turning lock to lock a few times should make it go away if not its the seals in the pump.

The train pulling to a stop (sqeak then horn type sound) that brakes make when they are sticking slightly sounds like they did a poor job of 're-furbing' your calliper. It's not uncommon for people to do a bodge job to try and fix it temporarily. I would have a look yourself and then make your way over to the other thread on here about plate lift to see what needs doing.

 

[944Fripp]

I think you're right on the money for the pump, I think it's the seals as the level remains constant. Is that a new pump jobby then?! What's that likely to cost, apparently I can get a refurbished one rather than a whole new one...advisable?!

As for the brakes, it's definitely not a train pulling to a halt sound. There's nothing high pitched to it, it's a low sound and does indeed sound just like the previously mentioned sound. I can't figure it out as it was all done at a very reputable garage who really seem to know what they're doing. It almost sounds like the disk is reverberating as the sound is so low in pitch and I can only hear it at very low speed (it's pretty embarrassing in a traffic jam especially as the car draws attention as it is!).

 

[sulzeruk]

The S2 I just bought is exactly the same Tom, it is the pads vibrating due to sticking in the caliper. I gave the caliper a steam clean whilst still on the car which helped for a few days. The only way to cure it is a full refurb of the caliper to get rid of the dreaded plate lift. It only became apparent when the car had been used for a few miles, obviously the pads heating up slightly, it was fine when cold. I have a very slight bit of shudder from the brakes so will chuck a new set of disks on when I do the calipers!
There is a replacement seal kit available for the power steering pump, it consists of an O ring, 1 seal and a shaped O ring! I am going to send a set off to be copied and flog them myself I think, Porscheshop want £25 for a set!!! They are not too tricky to repair yourself and will make the steering 10 times better!
Alasdair

 

[DivineE]

Pump re-built is fine. My friend who has zero mechanical ability re-built his own with a repair kit apparently its as easy as changing brake pads.

Which brings me nicely onto my next topic which is that sometimes brake pads can make noise at low speeds. Try taking the pads out and filing the front edge to make an angle. If the calliper is good this should cure it and hey you cant go wrong for the grand price of free.