Audi 100 S4 front brakes anyone???

Audimaan · 25-07-17, 01:05 AM

Attention needed for my Audi 100 S4 1992 please.
Im in need of front brake discs & pads on my Audi 100 S4. It has the UFO type discs set up at the moment but now needs replacing, These UFO type are now obsolete and ive heard i can use the set up of an A6 Quattro etc. Has any body got anything Suitable for me or has used an alternative set up to them orignal UFO's & can tell me exactly what is needed or where to buy from please ???

vorsprung durch technik · 25-07-17, 12:32 PM

As far as i know you'll only be able to use HP2 struts from the S6, and since they are
worth money now i haven't seen one being brocken for a while.
I guess Audi will have them but at a silly price.Best of luck looking.

Audimaan · 25-07-17, 01:01 PM

Quote:

Originally Posted by vorsprung durch technik

As far as i know you'll only be able to use HP2 struts from the S6, and since they are
worth money now i haven't seen one being brocken for a while.
I guess Audi will have them but at a silly price.Best of luck looking.

Hi is that the HP2 struts from the S6 on the same C4 platform approx 94 to 96 ?
Thanks.

vorsprung durch technik · 25-07-17, 01:06 PM

Yes,1994 - 1997.

spink · 25-07-17, 01:21 PM

You can fit urs6 HP2 calipers to UFO struts with a bit of modification,theres a thread on s2forum showing how to do it but cant find it at present since its been upgraded

Audimaan · 28-07-17, 08:07 PM

can any other audi model a6 struts etc be used e.g. the 2.8 quattro or any thing similar ???

shaun5 · 28-07-17, 08:35 PM

Quote:

Originally Posted by Audimaan

can any other audi model a6 struts etc be used e.g. the 2.8 quattro or any thing similar ???

Depends if you want big brakes, as ive said on s2forum, 2.8 cars only came with single piston calipers (ive got the complete set up) or i think ive still got a set of HP2 calipers from a S6.

vorsprung durch technik · 28-07-17, 09:23 PM

Quote:

Originally Posted by Audimaan

can any other audi model a6 struts etc be used e.g. the 2.8 quattro or any thing similar ???

No!! why would anyone want inferior brakes to what they already have? As i've said on S2 forum you need HP2'S from a late URS4 or from an S6.

Hanuman · 29-07-17, 03:59 PM

Well, if it's to keep a car running, in the absence of HP2 struts, other options ought to be explored.

HP2 struts are without a doubt the obvious choice; they were installed in S6. No messing, direct swap. I have them on two V8s.

Talking of which, the V8 in both 3.6 and 4.2 versions had the UFO disc. And the 4.2 engine was used in the S6, also. When audi America ran into warranty issues because of brake judder on the UFO discs, a retrofit program put the G60 Girling calipers on the V8, with 276x25mm discs from the 200 quattro/turbo. However, my maintenance manual for the V8 also indicates a later installation used the 288x25mm disc and single pot calipers of the C4 cars. I'm fairly sure this was not an option outside of the USA/North America.

UFO discs are 310x25mm with a single pot calliper, while HP2 are a twin pot caliper with a 314x30mm disc.

I'd imagine from an insurance point of view, going down in disc size would give the insurance company a lot of wriggle room regarding cover.

I'm not keen on the previously mentioned UFO strut modification to take an HP2 caliper, having looked at it myself. The bolt holes need to be sleeved to centralise the caliper, and the head of the bolt has a much reduced surface contact. HP2 caliper bolts are M14, while UFO caliper bolts are M12.
That's not to say that it can't be improved upon as an idea.
The other issue with modifying an UFO strut is the hub. It's a larger diameter than for a conventional disc setup, and the hub face is a slightly different 'offset', too. Again, not insurmountable, but needs accommodating.

I started sourcing a Mercedes disc (same PCD), to use with a radial mounted brembo caliper. Modifications would run to making an adaptor bracket to mount and centralise the caliper. It's just part of a project that's been on hold due to work issues in the last couple of years. The RS2 used adaptor brackets to mount the calipers, as have many other caliper conversions.

vorsprung durch technik · 29-07-17, 04:50 PM

Quote:

Originally Posted by Hanuman

However, my maintenance manual for the V8 also indicates a later installation used the 288x25mm disc and single pot calipers of the C4 cars. I'm fairly sure this was not an option outside of the USA/North America.

I'd imagine from an insurance point of view, going down in disc size would give the insurance company a lot of wriggle room regarding cover.

Those 288 x 25mm vented discs you mentioned with single piston caliper might be correct but i thought they only ever supplied the URS6 over in the US with the smaller disc you mentioned with the G60 callipers?

Those 288 x 25 vented discs were also the factory fitment for my very late 2.8 quattro and were in conjunction with ATE 57 single piston caliper.Could this be the set up your referring to?

I'm not bothered either way but if someones looking for 2.8 quattro ATE 57 callipers,i would strongly advise they are used on a 2.8 C4, in original extreme low mileage perfect condition, tested, with brand new 288 x 25 Brembo rotors i might listen to a reasonable offer.

Getting back to Audiman..........just look for HP2 struts and callipers and be done with it they are the perfect fit. There will be loads of HP2 struts in Germany for sale.Wont be cheap but what is nowadays concerning these hard to get parts in the UK.

29-07-17, 03:59 PM	#9
Hanuman Trickster Classic Audi Club Member Join Date: May 2009 Location: Heckling from the cheap seats, Phnom Penh, KoW Posts: 7,006	Well, if it's to keep a car running, in the absence of HP2 struts, other options ought to be explored. HP2 struts are without a doubt the obvious choice; they were installed in S6. No messing, direct swap. I have them on two V8s. Talking of which, the V8 in both 3.6 and 4.2 versions had the UFO disc. And the 4.2 engine was used in the S6, also. When audi America ran into warranty issues because of brake judder on the UFO discs, a retrofit program put the G60 Girling calipers on the V8, with 276x25mm discs from the 200 quattro/turbo. However, my maintenance manual for the V8 also indicates a later installation used the 288x25mm disc and single pot calipers of the C4 cars. I'm fairly sure this was not an option outside of the USA/North America. UFO discs are 310x25mm with a single pot calliper, while HP2 are a twin pot caliper with a 314x30mm disc. I'd imagine from an insurance point of view, going down in disc size would give the insurance company a lot of wriggle room regarding cover. I'm not keen on the previously mentioned UFO strut modification to take an HP2 caliper, having looked at it myself. The bolt holes need to be sleeved to centralise the caliper, and the head of the bolt has a much reduced surface contact. HP2 caliper bolts are M14, while UFO caliper bolts are M12. That's not to say that it can't be improved upon as an idea. The other issue with modifying an UFO strut is the hub. It's a larger diameter than for a conventional disc setup, and the hub face is a slightly different 'offset', too. Again, not insurmountable, but needs accommodating. I started sourcing a Mercedes disc (same PCD), to use with a radial mounted brembo caliper. Modifications would run to making an adaptor bracket to mount and centralise the caliper. It's just part of a project that's been on hold due to work issues in the last couple of years. The RS2 used adaptor brackets to mount the calipers, as have many other caliper conversions. __________________ I wish they would keep the damned Chinese away now that I can go home, so that I can enjoy Fish amok and a draught Angkor

25-07-17, 12:32 PM	#2
vorsprung durch technik 4 ring whore! Classic Audi Club Member Join Date: Feb 2014 Location: Near Watford. Posts: 7,753	As far as i know you'll only be able to use HP2 struts from the S6, and since they are worth money now i haven't seen one being brocken for a while. I guess Audi will have them but at a silly price.Best of luck looking.

25-07-17, 01:06 PM	#4
vorsprung durch technik 4 ring whore! Classic Audi Club Member Join Date: Feb 2014 Location: Near Watford. Posts: 7,753	Yes,1994 - 1997.

25-07-17, 01:21 PM	#5
spink Senior Member Classic Audi Club Member Join Date: Dec 2007 Location: yorkshire Posts: 1,525	You can fit urs6 HP2 calipers to UFO struts with a bit of modification,theres a thread on s2forum showing how to do it but cant find it at present since its been upgraded

28-07-17, 08:07 PM	#6
Audimaan Grown up member Classic Audi Club Member Join Date: Mar 2017 Location: WEST MIDLANDS Posts: 30	can any other audi model a6 struts etc be used e.g. the 2.8 quattro or any thing similar ???