S2 Brakes

[944cabby]

The old brake judder on my cab seems to have come back again and seems to get worse dependant on the road conditions.For example on a spin late this afternoon, on stretches of "good" surfaced road the judder was minimal,but still there.On bumpy surfaces (usual rural "b" roads) when i applied the brakes, it felt very bad.
I'm going to remove both front calipers tomorrow,strip them,clean and inspect (i stripped the passenger side front a few weeks back and also checked both front disks and it went away until now - pads also seemed to fit snuggly with no visible problems).
Thing is over the past month or so i've not taken her out much (probably twice per week) so i'm wondering if this would be a reason to cause the caliper pistons to start to sieze?If it is this, would a fluid change be sufficient and what should i look for when ispecting the pistons?
Does anyone else suffer with this intermittantly?

 

[TTM]

I experienced what seemed to be brake judder on my S2 some years ago but it appeared to be the ABS that was eratically going on/off because of a previously badly bled brake circuit.

 

[Fen]

Have you got Zimmermann disks? If so they seem to warp for no reason at all. My hearse is in tomorrow for a new pair on warranty as it has them on the front (never again) and they started to judder a couple of months ago.

 

[944cabby]

I'm not sure if these are zimmermans - i'll have a look through the service history.These are the ones that were on it originally and i swapped them over for new zimmermans as the originals needed skimming.One of the zimmermans failed the mot last march and i wasn't impressed with them anyway, so i had the originals fitted back on and skimmed.
They've been fine until recently which makes me wonder if it's maybe caliper piston related due to being used less.
TTM - did you're ABS light come on with the judder.

 

[TTM]

ORIGINAL: 944cabby
TTM - did you're ABS light come on with the judder.

No, it did not.
I think the ABS light comes on only when the ABS goes wrong - never seen an ABS go wrong in a 944 though.

 

[chrisg]

Jason

I'm not familar with the model years and minor differences to advise. I do know that on the G plate S2 I owned the Porsche lettering was embedded in the caliper as part of the finish. On the F plate Turbo S I currently own the caliper have the Porsche lettering raised in silver/ unpainted Aluminium as I believe you're describing.

I suspect that internally there will be no difference in the braking ability nor piston size. You may just find that a previous owner had a seized caliper or sheared a bleed nipple off and just replaced one calliper. If the aesthetics bother so much source a matching pair for the axle from E-bay, have them refurbed (new seals and plates) and then fit them ?

Chris

 

[944Turbo]

Is it a rear that has the sticker? I think the later cars 90ish on had the stickers,
Tony

 

[zcacogp]

Wot Chris Said.

There were differences in the castings as time went on, but the piston sizes are critical. They will need to be the same on each side otherwise the car will be unsafe. If there are differences, it is probably because one caliper has been replaced at some time (quite possibly with a new - but later - part from Porsche.)

However, thinking about it, if the pistons were different sizes from one side to the other then the car would almost certainly fail the MOT as the brakes would be unbalanced. So if you have an MOT then things are probably fine.


Oli.

 

[jmelhuish]

Thanks for the info. It is the rear and yes the car has a current MOT. I plan to refurb the calipers next year so I need to get a matching caliper to make a set.