8E0 Rear Brake Upgrade

[GT500]

I don't know if this helps...

Why not use 20Valve UR quattro rear discs?

They are vented and are 270mm. Have the correct hat and stud pattern.£70 odd a pair from the stealer.

Use S6 caliper, which is the same as the UR 20V. All bolts straight on and handbrake fits the same as original. I think the piston is 43mm, I can take a photie if anyone need to see it?

I have run this set up for the last 10 years on my UR.

Rob.

[1975DCS]

I don't know if this helps...

Why not use 20Valve UR quattro rear discs?

They are vented and are 270mm. Have the correct hat and stud pattern.£70 odd a pair from the stealer.

Use S6 caliper, which is the same as the UR 20V. All bolts straight on and handbrake fits the same as original. I think the piston is 43mm, I can take a photie if anyone need to see it?

I have run this set up for the last 10 years on my UR.

Rob.

Are you sure as the Ur20V has a height of 59,9mm compared to the S2's 39,7mm...
The Same applies for the front both Ur20V and S2 are 276x25mm but the height is different. The Ur20V has a height of 46,5mm compared to the S2's 56,5mm...

I don't know why the S2 is different in height (vice versa) or what Audi was uberhaupt thinking of going to smaller rear discs with the heavier S2!

[S2central.net]

UR 20Vs do NOT fit - the hat height is wrong for the S2... BTDT

[malfunkshun]

And the final word on the Avant conversion is...?

[raymor]

Well I'd like to know the answer, I've got all the bits and an Avant but no time just now....

Ben - S2Avant will probably know the answer shortly tho'

I'd never have thought there was such a thing as a braking 'dark side'... but there is - I can smell 8 pot RS6 calipers - if only I can get a set of original S8 Avus 18's

And the final word on the Avant conversion is...?

[NEO]

Have you done any more research in Coupé rear break upgrade? What's mounted at your car at the moment?

Its all plug and play except the handbrake - I haven't had time to follow through and solve the handbrake problem yet. I'm talking about the COupe of course, but S2avant is trying an almost identical setup on the Avant. All parts the same except his calipers are black in colour. That *should* bolt straight up and if it works on Avant, then it works on the Limo (Saloon / Sedan).

Paul

[VladaS2]

Yes Paul, enlighten us!

[S2central.net]

More to come on this real soon - I need to get the rear brakes sorted for this years MOT in Feb so I'll let you know more then... I have a cunning plan !

Paul

[NEO]

Weeee! Sounds interesting! Need something at the back to match my front RS6s.

More to come on this real soon - I need to get the rear brakes sorted for this years MOT in Feb so I'll let you know more then... I have a cunning plan !

Paul

[S2central.net]

I finally have an update for you - its been over a year in the making but hey --->

http://homepage.mac.com/nugentp/PhotoAlbum16.html

The final configuration for the S2 Coupe (NOT Avant or Sedan) is as follows.

300x22mm rear disc from neu S4 - part number = 8E0 615 601R (2-off)
Diameter reduced to 280mm - no other mods to disc - cost 20 quid for machineman

280x22 carrier from the S8 - part number = 4D0 615 425C (2-off)

Rear caliper from UrS6 - same as RR quattro - part number to follow
This caliper has a bigger piston than the S2 item. Topology is perfect.

S8 pads for those 280mm discs - part number = 1J0 698 451L
The pads are sited perfectly on the disc surface by the carrier. No overhang.

4 x 50mm long caliper carrier bolts - part number = N101 815 02
Shortened to 35mm. The 30mm original bolts are too short cos of carrier spacers.

12 x M10 washers approx 1.25mm thick
Arranged three deep for a ~4mm spacing to centre the S8 carrier over the disc
These are a bit fiddly to fit cos they get sandwiched between hub and carrier - a properly made spacer bracket would be more elegant and easy but its no biggie.

To complete the transition I renewed the hydraulic lines to the caliper - same as S2 hose along with new spring clip for the union bracket. Part numbers below:

S2 Coupe rear hose = 893 611 775 (2-off)
Union clip for hose = 4D0 611 715B (2-off)


Fitment to one side of the car is complete - bad light stopped play ! My rear discs are now bigger than my fronts until I get the 996 monos fitted with A8 323x30 discs but thats another entirely more easy story. This exercise is just to get me thru MOT - then I'll get to the front anchors

This disc reduction to 280mm was only necessary on the Coupe cos of the handbrake routing to the caliper - the UrS6/RR caliper is a perfect fit on the Coupe application.

On an Avant/Sedan, you can run with the 8E0 disc at full size of 300x22 using the corresponding carrier, caliper and pads - not cheap but a mighty upgrade for the Avant/Sedan and the handbrake combination of that 8E0 caliper works on the Avant/Sedan.

Parts list for the Avant/Sedan conversion is as follows -
Disc = 8E0 615 601R (2-off)
Carrier = 8E0 615 425B (2-off)
Caliper = 8E0 615 423C and 424C
Pads = 4B3 698 451
Hoses = 8E0 611 775H (2-off)
Carrier bolts = To be added (normal S2 avant/sedan items as no spacer required)

Sorry it all took so long - it has been an expensive process at times, but the 8E0 calipers, carriers and pads will go to a good Avant running home.

The total price of everything for my vented rear disc conversion on the S2 Coupe from S4/S6/S8 parts isn't as lairy as you might think. Most expensive item is the S8 carriers as you'll not find them in a breaker easily. The discs are cheap. The pads aren't expensive and I paid about 100 quid for two good calipers of a 1997 S6 from a breaker.


Paul

PS - Note that whilst its not necessary to change your handbrake cable for this conversion you might decide to do at this time just to refresh everything on the rear brakes. If you do, then note the following :

Coupe handbrake cables are different each side - 893 609 721E and 893 609 722E
The Coupe handbrake fits the S6/RR caliper with spring clip 857 609 745A (2-off)

The Avant/Sedan handbrake is same each side = 8A0 609 721AD (2-off)
A different retaining clip is required for that on the 8E0 caliper = 171 611 819 (2-off)

[T2Andy]

Paul you are the man will do this myself with a little help

[s2driveruk]

top job Paul, gonna have to unsieze the rears on mine this morning and i really want to fill out those rear 18's better, this looks like a good first step

[MidnightBlueS2]

I've been putting off replacing my rear discs, waiting for an upgrade, when and if it would arrive and it looks like that day HAS arrived...

Superb job Paul !

[S2central.net]

Did the 2nd one today and it was all fine except for the stress of having to reduce tension on the handbrake cable to get it to fit on the 2nd caliper. That requires unbolting one of the heatshields around the propshaft & exhaust to gain access to a 10mm adjustment bolt on the end of handbrake lever. Bit of a pain but no biggie - have had to do that before when replacing stock rear calipers on a 20VCQ.

Only issue I have is that the rear brakes haven't bled properly. I suspect a dicky 1-man (eezibleed) kit has sucked air in. Need to bleed it again.

Paul

[s2dude]

Great job Paul..
Nice work there
I was thinking, is it possible the cause of your soft brake pedal isnt due to air in the system but because the rear calipers are now larger than the fronts (and stock)...meaning the bias proportioning is out of kilter??
As in its having to push a lot more fluid to the rear to operate the calipers which is causing the long travel??
How about trying an A8 brake bias valve?? or similiar..as I dont think bias is adjustable on these cars is it? (or whatver the part is on the S2)
Just a thought. May be a load of tosh I'm talking though