S4 brakes

[Tractor Dave]

Hi guys. I bought these on eBay, described as B6 S4 rear brakes. The numbers on them don’t seem to correspond with what I was expecting. They have TRW and the Audi logo as well as E106 6NO then 9250c on one side and 9251c on the other. Anyone know what I have here?


Thanks

Dave


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[Vorsprung durch Technik]

Sorry i can't help but just wondering why you didn't go for UrS6 rear calipers?

[Tractor Dave]

These came up for a good price and I haven’t seen any URS6 calipers, carriers etc for sale. I expect they would be out of my budget as well.
This car has already financially ruined me and I’m not half done!


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[Error404]

The B6 S4 setup is a better option as the carriers are larger - they are designed for a 300x22mm disc rather than 269x20 as per the UrS. Calipers share the same size piston but B6 bits are easier to find. Before the UrS guys get defensive, I have no axe to grind here as I have UrS rear calipers with B5 RS4 carriers and rotors on the coupe


Dave, numbers are not very helpful since the castings rarely seem to have anything relevant on them.
It might be easier to try and identify them from the carriers.


B6 S4 numbers:
Right rear caliper - 8E0 615 424 C
Left rear caliper - 8E0 615 423 C
Carrier (not handed) - 8E0 615 425 B

TRW numbers:
Right rear caliper - BHT258E
Left rear caliper - BHT257E
Carrier: BDA632

HTH

[Tractor Dave]

Thanks for all the info. Everything is covered in crud at the moment. I will give them a good clean and check numbers tomorrow. The piston size is approx. 41mm.
The discs are 300x22. They came still attached!

[Error404]

OK well then they are almost certainly B6 S4

[Vorsprung durch Technik]

The B6 S4 setup is a better option as the carriers are larger - they are designed for a 300x22mm disc rather than 269x20 as per the UrS. Calipers share the same size piston but B6 bits are easier to find. Before the UrS guys get defensive, I have no axe to grind here as I have UrS rear calipers with B5 RS4 carriers and rotors on the coupe

HTH

I'm fine with it, i can understand someone wanting a 300 X 22 rear disc for serious S2 bhp figures but i believe the 269 x 20 is more than enough for an S2. Plus the discs will be cheaper and weigh much less. Granted UrS6 rear callipers and carriers aren't easy to find but are a really nice classic set up that originated of the Ur Quattro itself.

Out of interest how much is the B6 S4 carriers callipers and discs?

[Tractor Dave]

I must admit that I didn't realise UrS6 calipers would fit, so wasn't even looking. I researched the options here and on the internet and chose the S4 upgrade because apparently it's a straight fit. I didn't have any brakes at all, front or rear and was first of all going to go with standard spec but followed the advice from here to upgrade instead. I'm not planning any huge power increase but it's always nice to know the car will stop well. I already have 911 front calipers ready to go.

I shopped around for these. Typically, B6 S4 brakes (with carriers) seem to go for about £250 plus postage. I managed to get these for £120 delivered. The discs are close to the wear limit but I bought a new set from AutoDoc for £30 (Ridex) and they seem good quality. I even got the back plates but don't think they will fit my hub. It was a bit of a gamble though as they were bought unseen. They were still on the car when I enquired.

The calipers will need stripping, painting and an overhaul. AutoDoc sell pistons and new seals but I will check the size before I order.

Thanks again for all the advice from everyone here.

[Tractor Dave]

Calipers and carriers cleaned up nicely. I found a number on the handbrake mechanism starting 8E0, so I think I'm ok. Did a trail fit on my hub carrier and the holes line up nicely.

I painted the carriers in VHT black paint. They have just come out of the oven after curing on a low heat. I'm not too happy with the finish though, which is a very dull matt black. Any suggestion on paint for calipers/carriers?

[Tractor Dave]

Also noticed that the handbrake cable connector has a ball on the end whereas my new cables have a rectangular connector which I don't think will fit. Have I got the wrong handbrake cables? What connector should the S2 Avant have?