Euro 928

Hello, I have a 1985 928 Euro 5 speed. And I have an oppertunity to get the brakes from a 1987 928 S4. Will these brakes be an upgrade worth the expense? Seller is asking $600 for Calipers, Rotors, and Hoses. What will I have to do to put them on my car?

Thanks

davek9

I think you will need the S4 suspension and hubs and axles too.
Your brakes are single piston (floating) correct?

JHowell37

You'll need the front control arms and spindles from the S4, or you'll need early spindles, adapter brackets, and 993 front rotors. The rears just require some thick washers to shim the calipers, but you can certainly get the rear hub carriers and put them on.

123quattro

You would want the front control arms to go with the calipers. Rears bolt on. $600 is a decent price for the parts. Front rotors will be about 3/4" bigger than what you have.

James Bailey

If you have ABS now there are differences as well......if you want it to work.

Bart-Jan

But is there a need to change over apart from the looks? I've read several times that people that have done the swap actually did not notice an improvement over the S floating calipers...

tilac999

It's eye candy. They look awesome but the S brakes are more than you'll ever need. Not worth the trouble in my opinion.

Mrmerlin

didnt a few others simply buy adapters to mount the front calipers Ken Rudd for example?
the rear calipers should bolt on and the backing plate should be swapped as the rear rotors with the S4 brakes are bigger.
Same for the front backing plates. that way you keep the ABS if the car has it,
Thus no swapping out LCAs or spindles or upper control arms

GregBBRD

The ball joints end up hitting the rotors, when using any of the adaptors that I have seen. The ball joint can be "ground down" some, but they still hit at the extremes...unless you grind on them until they are "unsafe".

I have not tried the pieces that Ed Standke is making.

The "correct way" to do it is with all of the '87 control arms, spindles, and uprights.

Big improvement in braking, BTW.

KenRudd

Bart-Jan-
Check these threads:
https://rennlist.com/forums/928-foru...-for-86-a.html
https://rennlist.com/forums/928-foru...s-on-85-a.html
https://rennlist.com/forums/928-foru...e-upgrade.html

They all relate to similar situations. On my 86, I ended up using the PerfexMfg kit to mount GTS Calipers to my stock 86 front spindles, and a couple spacers/washers to mount rear S4/GTS ( same) calipers on the rear. This let me keep my stock ABS. I had to tweak some dust shields as well, but that was minor. The Perfex kit is designed for GTS calipers, but contact Ed Standke ( on this forum or at perfexmfg.com) to see about S4 caliper application.

KenRudd

150mph is also more than you ever need, but we all seem to think we have to have a car that will do it.

For street use , the S3 brakes are certainly adequate. However, I can tell you from experience they are not adequate if you plan on using your car at the track on a regular basis.

GlenL

I disagree with that. Get better pads. Even with wider DOT track tires I can lock the brakes. Nothing more is needed.

JHowell37

I've been running adapters and early spindles on my '85 w/S4 calipers for 60K miles and have never seen any evidence of contact between the rotor and the ball joint.

James Bailey

With S brakes at Fontana where we run the front straight go through turns one and two on the gas before slowing for a quick 90 degree left and right......with race pads I found that I was pushing pretty hard on the pedal as I got close to that 90 left turn thinking it was probably good that they just coned off the back straight !! The old very brown is not that fast but was rolling pretty good on that big track.
That said for "normal" street driving at reasonable speeds S brakes can work very well they just lack the extra rotor mass, extra leverage for modulation, and somewhat bigger pads with staggered size 4 piston design, and the cool PORSCHE logo.

GregBBRD

Have you looked at the back side of the rotor and inspected the ball joint?

If you are running the S-4 rotor, along with that caliper, on an '85/'86 spindle, it is virtually impossible for the ball joint to not hit....