anyone here with a S2 Coupé and 312mm rs4 b5 rotors on the rear?

[S2central.net]

I'll dive into family album tomorrow to see what alternatives exist. I have a feeling the B5Q rear hub is not unique to the RS4. Could be wrong though.

[macspring]

Paul,

I took from Wolfgang's post # 10 that an B5 A4 1.8T quattro rear hub would be OK and therefore work for all S2 Avant owners ?

Hope I'm not wrong ?

[Jas11n]

Nice solution.
Just close your eyes, sit down and hold your breath to the price of the B5 RS4 floating rear discs























Around £210.
Oh....that's "each" by the way

[S2central.net]

Good grief... Presumably there are cheaper aftermarket discs for a bit less cash ?

[quattro]

no unless you go for custom hats and rotors there is no aftermarket solution foe the rs4/6 and R8 as i was looking in to something similar not so long a go!

[S2central.net]

OUCH on the wallet then - think I'll be happy with B7 S4 300x22 discs (spun down to 280) for now on my Coupe !

Here is a thought though - the B5 RS4 calipers with 22mm disc accommodation would work for me if the handbrake and such is as per B3Q Coupe from factory - I assume they are light alloy caliper and not the big steel old school one. My old RR calipers are getting a bit sticky so I'll have to weigh up some options before next MOT.

Great thread this !

[quattro]

Might get shot down in flames here but do the 3.2 V6 and 225 TT 22mm rear calipers have any chance in this, the only thing i can think of is the pads might be smaller than of the S4/8 or rs4 calipers.....

[S2central.net]

Dunno - but the Handbrake is the trickiest thing to work around if it doesnt line up as factory location...

[quattro]

After looking at photos for the last 30 min the tt caliper is a lucas 38 i guess 38mm piston and the S4/8 caliper is a lucas 43 again 43mm piston i assume hand brake looks identical to the S4/8 caliper, so from this information i can only shoot my self down as this will lessen the braking force which is opposite of the whole upgrade....

[S2central.net]

@Wolfgang - can you please post a photo to show how RS4 caliper connects to B3Q (S2) handbrake.

I had a look around family album and confirmed the following -

RS4 rear hub = 8D0 501 653B = same as any B5Q

RS4 caliper piston kit = 4D0 698 671 = same as many other 43mm piston caliper

The B5-S4 has 256x22 discs - not so exciting but I wanted to see if caliper is common to RS4 - it is NOT, but it absolutely is 43mm piston and might be interesting for us here.

The B5-RS4 caliper (8D0 615 423D and 424D) seems to have a hydraulic line with banjo bolt - as per the big ATE calipers on B6S4 for example.

The B5-S4 caliper (8D0 615 423C and 424C) uses the 'old style' hydraulic line that we find on B3Q caliper.

I therefore have a theory that B5-S4 rear calipers will work on B3Q instead of RR/UrS6 when running 22mm disc conversions. This caliper might be steel item as opposed to lightweight alloy on RS4.

There remains the question on handbrake as the B5-RS4 lists different cables that the other B5Q machines - so I am wondering if both calipers are straight compatible onto B3Q (S2). Photos would be great.

Cost brand new of B5-S4 caliper is roughly £100 each from new.

A also have a theory that the 310x22mm discs and carriers from armoured D1A8 will work on rear of B3Q. The discs are cheap but the carriers are outrageous - hence I am not placing that bet with cash. Thats a bit of a side topic though.

[S2central.net]

The plot thickens... Assuming the pic below is correct of the B5-S4 caliper (NOT RS4) then it looks more useful to the B4Q (Avant) people here - simply because of handbrake. Maybe the RS4 caliper is by fluke the right orientation for B3Q - but its odd if that is the case.

http://www.worldimpex.com/parts/genuine-part-brake-caliper-left-rear_84840.html

[S2central.net]

And then I find a picture of B5-RS4 caliper here - http://www.brakeparts.co.uk/ - which looks like is not easily compatible with B3Q - the Coupe - it looks like form factor of the B4Q application.

Sorry to woffle on here, but I need to see how the B3Q handbrake works with this RS4 caliper... they are a good price from the right place - they must be common fitment on other cars in some volume.

[Wolfgang]

hey guys,

I´m going to use the girling 41/43 caliper cause of the silly handbrake cables on the t89q, this is the only reason. If you´ve got a B4 Quattro no matter in what version ( s2, competition, 2.0quattro...) these calipers are the wrong ones for you. You definetely have to look after RS4 calipers or something like this because of the handbrake.

The reason why the rs4 caliper works is simple, B4Q and all A4 B5 Quattros (also S4 B5, and RS4 B5) have nearly the same (or exactly the same) rear wheel bearing housing/wheel bearing carrier. The RS4 wheel bearing housings i bought had an 8A0 part number on it...

If you´re running an B4 Quattro i´m quite sure that you don´t need to change hubs because of the hub-offset. This has to work with RS4 B5 caliper carrier, rs4 b5 brake discs, rs4 b5 calipers and original B4Q handbrake cable.

i´m going to compare S2 avant/sedan rear wheel hub with the rs4/s4/a4 quattro ones. if these hubs are the same concerning the brake-disc-offset, it´ll work.

You can´t use the RS4/S4/A4 quattro B5 rear wheel hubs on the big B4Q, (S2, 2.8V6, etc) cause the driveshaft-splining (hopefully the right word ) is on the RS4 SMALLER than the S2/RS2 ones... sounds strange but it´s a fact...

the girling 41/43 caliper is used on following cars:

Audi Urquattro 20V
Audi 200 20V
Audi V8
Audi UrS4 or however you call it, in germany they say: Audi S4 C4
Audi UrS6 same as above, Audi S6 C4
and in some early A8 or something if i remember correctly

The RS4 B5 has whatever for calipers, i don´t know?! and to be honest, i don´t care, cause this caliper is useless on the coupe.

the piston diameter is 41mm.

@s2central.net

don´t know how the grip is improved by 7mm more track on each side.. if i´ll feel more grip i´ll tell ya. theoretically it should be more grip, there is no discussion about that...

@david in dublin

i haven´t got any partnumbers here, sorry. You can be sure that everything is from the RS4 B5. I´ll post the numbers tonight, i promise.

And no i haven´t got a foto with the caliper on the disc. the calipers are getting powdered at the moment...

And yes, you´re right, an A4 1.8T Quattro rear wheel hub should work nicely.
(according to ETKA, i didn´t try this wheel hub... )

@jas11n

Yes, you´re right, the discs are expensive, but this dues to the fact that the disc is steel and the "hat" is made by aluminium...

And to be honest i spent thousands of damn euros in this car so i don´t gave a **** about the price of the discs.
Knowing now that it´s plug´n´play makes it much more easy to forget about the spent euros... AND if nobody tries, we´ll never find out...

You can also take the not vented discs, these are a little bit cheaper... 500€ the set i think...

Here is a thought though - the B5 RS4 calipers with 22mm disc accommodation would work for me if the handbrake and such is as per B3Q Coupe from factory - I assume they are light alloy caliper and not the big steel old school one. My old RR calipers are getting a bit sticky so I'll have to weigh up some options before next MOT.

But you´ve forgotten that the S4 B6 calipers have a wider distance on the holes where you bolt the caliper on the caliper carrier.

Girling 41/43 are the same distance like the rs4 b5. Running the s4 b6 caliper carriers, means you can´t use girling 41/43 and rs4 b5 calipers...

Moreover the handbrake cable is the same way solved as it´s on the B4Q... totally different to your G41/43 from the RR urq...

@quattro

TT calipers? Golf 4 parts? on an audi?

Don´t know to be honest but i´m quite sure that there are much more different parts on it than it´s on the RS4 B5....

And as far as i know the rear brakes on the big TT Quattros are the same as R32. and this is think 254mm diameter disc or something?!? can´t believe that this is going to work..

The bigger piston diameter makes a longer brake-pedal before it brakes, but if it brakes it´ll brake definetely more than before...

[macspring]

Wolfgang,

That's some reply.

Can believe this attitude to Avant owners though - Quote - "The RS4 B5 has whatever for calipers, i don´t know?! and to be honest, i don´t care, cause this caliper is useless on the coupe".

In relation to the TT caliper, I can advice that in the recent past I tried TT light alloy calipers on the Avant and they would work fine except the bracket for holding the hand-brake cable and the lever for the nipple of the hand-brake cable is in the wrong place. Additionally if they had to be fitted to an Avant one has to hacksaw off the bracket for the outer part of the hand brake cable as it fouls on the thick metal tie rod at the rear of an Avant hub.

As the rear of an B4 S2 Avant is very very similar to the rear of B5 quattro Avants, the most likely answers for rear brake upgrades lies with Audi B5q rather than any other car, although happy to be proved wrong.

I must say the oem rear brakes on an Avant work fine but look tiny especially with say Avus S8s, and so there must be a huge untapped potential market for various Avant upgrade kits to say 256 vented / 300 vented / 312 vented.

Keen to see how this thread develops.

Wolfgang, while I know you have a Coupe, but with your knowledge gained to date any further input for Avant owners would be greatly appreciated.

[S2central.net]

OK - So Wolfgang has verified my fear for the B5 calipers - S4 or RS4 - they will ONLY work on B4Q because of handbrake cable.

So Wolfgang is using same 22mm caliper as me on the B3Q rear - this makes perfect sense. The only lightweight alternative I know to that caliper is from A8Q with 280x22. This works with a different hydraulic line but perfect otherwise.

I know all about the caliper spacing issue with B6-S4 so that is understood.

For B4Q I believe the following options exist - depending on depth of pockets...

1 - All of the B6 S4 setup with 300x22 discs, carriers, pads and alloy calipers. The handbrake lines up as factory. Only difference I know of is the hydraulic line but from memory the B6 hose is long enough to attach to solid line of B4Q. Expensive on calipers & carriers unless you get em cheap in a breaker.

2 - Variation of (1) with the B6 disc spun down to 280mm, select the A8Q 280mm carrier and a B5Q (or B5-RS4) rear caliper. Use same pads as A8Q. 100% bolt on allegedly with handbrake and hydraulic as factory.

3 - Alternative caliper for (2) is from A6AR (allroad) circa 2001 - alloy caliper with same hydraulic & hbrake. This is a 38mm caliper so perhaps not ideal... There is an expensive 43mm version on the V8 allroads.

4 - B5 RS4 at 312x22 with discs, carriers, pads and calipers. Also needs B5Q rear hubs to correct disc offset.

5 - Variation of (4) with use of 22mm B5Q rear caliper (steel) from B5-S4...