8E0 Rear Brake Upgrade

[Corey]

The UrS4/6 carrier bolts on the inboard side of the hub, whereas the carrier for the coupe bolts to the outboard side of the hub carrier. If the outboard side of the hub on the UrS4/6 is not machined, it may be hard to install.

Greg W.

That I know, don't worry I know someone who could machine them if necessary

[90quattrocoupe]

Well done for this Paul, I must agree that I am amazed about this bolting straight on. Theoretically this should also bolt onto the urS4/6 rears then? As you were using the carrier?

The UrS4/6 carrier bolts on the inboard side of the hub, whereas the carrier for the coupe bolts to the outboard side of the hub carrier. If the outboard side of the hub on the UrS4/6 is not machined, it may be hard to install.

Greg W.

[Ross]

Looks really good Paul! Just as I thought I had all the projects ever in line, you go and add another to my 'wish list'

Sod the handbrake, mine hardly works anyway seriously, if the caliper fits like everything else this is going to be a mighty rear brake set-up with bolt-on parts right?

What's the costs looking like for a full rear set-up with this conversion, assuming it all works once fitted?

Ross

[Corey]

Do you have a measurement from the inner mounting face to the inner face of the braking surface of the 8E0 disc?

Other mods are not a problem but it would be nice to just bolt on.

[S2central.net]

Could have knocked me down with a feather... I was grinning like a cheshire cat last night about this. Only concern is the handbrake cable. If Twoqu's photo is right then its great that we have leading caliper design but I think a longer cable or different routing will be needed for the handbrake.

You are right about UrS4/S6 rears with respect to axial position of the 8E0 carrier, but don't the UrS4/S6 discs have a much larger total height than S2 ? In which case the 300x22mm 8E0 disc won't work without other mods.


Paul

[Corey]

Well done for this Paul, I must agree that I am amazed about this bolting straight on. Theoretically this should also bolt onto the urS4/6 rears then? As you were using the carrier?

[S2central.net]

Oh it just gets better and better... My bench meaurements on axial clearance were bang on. Only a dry fit would confirm radial position of the carrier -

http://homepage.mac.com/nugentp/PhotoAlbum12.html

Surely it can't be a fluke... The brake man at Ingolstadt must surely be on old 89/8B Coupe owner who fancied bigger more modern brakes.

The photos speak for themselves - the disk clearance to the carrier looks perfect without any spacers. Just bolts right up guys.

I'll get the calipers on as soon as I get them - they are on backorder !!!


Paul

[90quattrocoupe]

Paul,

Hopefully, here is a pic of that caliper in situ:

Well that is definitely a front pull Ebrake. Well Paul, let us know if can get the Ebrake cable to work.

Greg W.

[twoqu]

Paul,

Hopefully, here is a pic of that caliper in situ:

[S2central.net]

Hopefully these photos make it a bit more real, and a lot less dull

http://homepage.mac.com/nugentp/PhotoAlbum11.html

Hopefully have more info on Sunday evening - finger's X'd...

Paul

[S2central.net]

OK the 8E0 carriers arrived from my favourite Audi dealership parts man today. Spent a good hour or two tonight measuring and comparing with UrS4/S6 carrier.

I'm hopeful of getting an hour or so at the weekend for a dry fit of the 8E0 carriers and discs.

Lots of photos taken which I hope to post later... but here's the scoop folks.

I positioned the UrS4/S6 carrier on the 8E0 disc. Because the S4/S6 disc is 269x20 the gap for the disc on the S4/S6 carrier is approx 22mm - making a nice fit on the 8E0 disc for reference purposes. Remember we know the S4/S6 carrier bolts right up to a modified A3 front disc which has same (or very close) total height as stock S2 rear disc.

With me so far ?

I confirmed Ben's measurements of 90mm carrier-hub spacing and yes the bolt thread is the same. I also confirmed the mad 145mm caliper bolt spacing and the bolt threads are same as normal there too.

The disc gap in the 8E0 carrier is a liberal 28mm which means for the carrier to sit centrally over the disc (which I assume it does) there is approx 3mm gap on each side. I used some spacers to site the carrier onto the disc and found that the carrier-hub mounting face sits about 5mm further INboard than the reference S4/S6 carrier.

This is great news as the 8E0 disc will naturally sit 5mm further OUTboard than the stock S2 rear disc. Based on bench measurements comparing stock S2 disc with the 8E0 item.

Still with me ?

Like I say - won't know for definite about the radial position until I dry fit, but the vibe is good here...

Only other unknown remains the funky 8E0 calipers because if the handbrake mechanism is incompatible then its going to complicate things and/or raise the price significantly.


Paul

[S2central.net]

Just found another option in the family album. Not a cheap one mind, but here goes:

There is an option for 310x22mm rear brakes on armoured A8/S8. These use the same alloy calipers as the 280mm A8/S8 rears (4D0 615 423/4 E) that MarkH fitted to the A8/S8 carrier (4D0 615 425C).

The carrier for the armoured 310mm brakes is 4D0 615 425D - at a whopping £167 each list price. These should work with A8/S6 or UrS4/S6 rear calipers as the spacing will be right. Whether this carrier works with the 8E0 (300mm) on the S2 rear without serious surgery remains to be seen.

Tis an option worth looking at - IF and only if the 8E0 carriers and calipers prove impossible.

Paul

[twoqu]

[S2central.net]

Paul,

My concern was for your wallet!
But if you are going to buy the whole set up on the hope that it is going to fit, good luck to you! Obviously there will be no compatability problems.
Those pads are completely different. It looks as though they slide in a channel approx in the middle of the pads whilst normal ones slide on a ledge at the rear. I guess it also means that they are going to be more expensive!
Still it looks like if you were fortunate enough to find any of those models in a brakers, you could use the calipers!
The point I'm making is that although the discs might make suitable candidates, it doesen't look like you can pirate bits from another model or use affordable secondhand components.
Still someone has to have a go

Don't worry too much about price here - there are mighty useful discounts available to Audi UK on brake parts at the minute. I can't say too much at the moment but this is going to be cheaper with brand new parts than the 280mm conversion that uses A3 front discs, A8 carriers & exotic alloy A8 calipers.

My whole attitude to this one has been to just buy all the bits and see if it can be made to fit... Otherwise we could talk about it here forever. Anything that doesn't work will end up on eBay and I shouldn't lose anything.

Paul

[Stick Insect]

@Stick - I'm not anti Ford parts really. Hey I drove a Mustang for three years... Surely that says something. I rather doubt that the Ford Scorpio 300mm vented disc will fit the S2... and its even more unlikely the Ford carrier will be useful but for sure they may have used different varieties of rear Girling calipers that could have uses. Don't forget all my intentions here are for the Coupe, but the Avant has a different rear caliper 'cos the handbrake mechanism is different - some abnormal sources of calipers could be useful for the Avant folk.

Anybody know if a Girling catalog is available - on line or in print ?

Paul

The ford Scorpio ( 5 stud) disks do indeed fit with the centre machined out slightly. The hat is too high though. I was wondering if there was a rear hub which has 10mm more offset and if you were using spacers you could do without them, the scorpio caliper brackets would then have enough clearance and the caliper looks fine ( don't know about the handbrake actuation)

More grist for the mill.

David