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  • Alternative rear caliper for S2 Avant

    I had to renew a caliper on the allroad but ordered a pair so I had both sides fresh. These are 100 ish from audi but can b found on eBay for 70ish if you are lucky.

    I compared these side by side with S2 Avant rear caliper. They are going to bolt on fit with same rear handbrake mechanism and securing clip. Same 38mm piston and S2 pads will work. The only difference is the hydraulic hose fitting at the caliper. Either a custom hose or maybe something else off shelf will work. This is for NON vented disc.

    the part numbers are 8E0 615 423A and 424A. These are light alloy calipers and have a much superior handbrake mechanism to old S2 design.

    The main upside from this is that I believe the alloy caliper from vented rear on allroad / C5-S6 should also bolt on to rear of S2 Avant using 280mm discs, spun down from 8E0 300mm and with A8 carriers. This should be a 43mm piston.

    Sorry if this is a bit confusing - I'll post more details later when I can check into an even better idea with something bigger.
    Paul Nugent
    Webmaster http://S2central.net
    Administrator http://S2forum.com

    1994 S2 Coupe ABY - aka Project Lazarus
    2001 A6 allroad 2.5TDi - family tank
    2003 S4 Avant 4.2 V8 - daily burble

    Purveyor of HomeFries and Exclusive agent for Samco hose kits (S2/RS2)

    There are only 10 kinds of people that understand binary - those that do, and those that don't

  • #2
    The 43mm rear caliper used on vented applications (22mm thickness) for A6/S6 quattro is also used on vented rear of Passat 4motion

    4B0 615 423 & 424 - these are expensive at £200 ish each from dealers.

    There is a M10x310mm long hydraulic hose with correct fitting for caliper end as 4B0 611 775 C
    A 350mm hose is used on the allroad as 4Z7 611 775 A

    Both of these are a bit longer than the M10x210mm used on S2
    On the passat application there is an M10x280 as 3B7 611 775 which is perhaps better

    I have a feeling that this 4B0 caliper will work with the following disc and carrier from armoured A8Q applications (310x22mm)... I don't know 100% if the hat height is perfect but bearing in mind the A8/S8 carrier for the 280mm disc is pretty perfect then I am fairly confident.

    4B0 615 423 & 424 - these are expensive at £200 ish each from dealers.
    Rear Disc = 4E0 615 601 A (50 each ish - these are 5 x 112 and right size centre hole)
    Carrier = 4D0 615 425D (expensive mind you)
    Pads = 4D0 698 451E (sized for this 321 disc and with caliper on armoured A8 except for the handbrake mechanism.. remember that the A8/S8 caliper works with B2Q/B3Q but not B4Q)

    This should be a bolt-up vented rear conversion for B4Q with 5-bolt hub including S2 - not a cheap conversion of course.

    Anybody wanna try it ?
    Paul Nugent
    Webmaster http://S2central.net
    Administrator http://S2forum.com

    1994 S2 Coupe ABY - aka Project Lazarus
    2001 A6 allroad 2.5TDi - family tank
    2003 S4 Avant 4.2 V8 - daily burble

    Purveyor of HomeFries and Exclusive agent for Samco hose kits (S2/RS2)

    There are only 10 kinds of people that understand binary - those that do, and those that don't

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    • #3
      Oh and of course swapping the rear caliper with these gives us a 310x22 conversion that should bolt right up to a 5-bolt B2Q/B3Q (incl S2) using 43mm caliper.

      Either 4D0 615 423 E and 424E (light alloy lucas caliper from A8/S8)
      or 447 615 423 and 424 (iron girling from RR/UrS4/S6)

      Cool... allegedly
      Paul Nugent
      Webmaster http://S2central.net
      Administrator http://S2forum.com

      1994 S2 Coupe ABY - aka Project Lazarus
      2001 A6 allroad 2.5TDi - family tank
      2003 S4 Avant 4.2 V8 - daily burble

      Purveyor of HomeFries and Exclusive agent for Samco hose kits (S2/RS2)

      There are only 10 kinds of people that understand binary - those that do, and those that don't

      Comment


      • #4
        Paul,

        Whats the chance of this fitting the coupe?

        If the brackets are really dear and it works... Could be worthwile asking Kev (Bambridge) to machine a version...


        sigpic

        New S2 - S8 & RS2 -RS6 Keyrings

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        • #5
          rear carriers are more complex to fabricate than fronts but I suppose its feasible...

          The only risk here is that hat height on A8Q rear discs could be wrong for the S2 - I have NOT seen these discs, but the 310mm rear carrier should be sweet on S2 as the offset for 280mm carrier on A8Q was and that should be same dimension on A8Q.

          Only way to know is for someone to take a punt on a pair of A8Q 310x22 discs and measure them... If they don't fit S2 then something else will need to be sourced. From memory, the total hat height that works for S2 is 40mm - ie the distance from most inboard disc surface and the mating surface with the road-wheel.
          Paul Nugent
          Webmaster http://S2central.net
          Administrator http://S2forum.com

          1994 S2 Coupe ABY - aka Project Lazarus
          2001 A6 allroad 2.5TDi - family tank
          2003 S4 Avant 4.2 V8 - daily burble

          Purveyor of HomeFries and Exclusive agent for Samco hose kits (S2/RS2)

          There are only 10 kinds of people that understand binary - those that do, and those that don't

          Comment


          • #6
            And the plot thickens - there is another version of the 310x22 rear disc on A8/S8 - this is 4E0 615 601 K which was introduced mid MY2005 - must be a dimensional change
            Paul Nugent
            Webmaster http://S2central.net
            Administrator http://S2forum.com

            1994 S2 Coupe ABY - aka Project Lazarus
            2001 A6 allroad 2.5TDi - family tank
            2003 S4 Avant 4.2 V8 - daily burble

            Purveyor of HomeFries and Exclusive agent for Samco hose kits (S2/RS2)

            There are only 10 kinds of people that understand binary - those that do, and those that don't

            Comment


            • #7
              Looking good - smells like a small spacer on the carrier will work as the disc height is 42mm - dunno if this is the 'A' or 'K' disc yet
              Paul Nugent
              Webmaster http://S2central.net
              Administrator http://S2forum.com

              1994 S2 Coupe ABY - aka Project Lazarus
              2001 A6 allroad 2.5TDi - family tank
              2003 S4 Avant 4.2 V8 - daily burble

              Purveyor of HomeFries and Exclusive agent for Samco hose kits (S2/RS2)

              There are only 10 kinds of people that understand binary - those that do, and those that don't

              Comment


              • #8

                sigpic

                New S2 - S8 & RS2 -RS6 Keyrings

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                • #9
                  Further searching is telling me that 'K' superseded the 'A' part and that a '3D0' version of the 310x22 disc used on VW Phaeton... Think its a go - worth a punt certainly...

                  Also if 310mm hat height for A8Q works good then so might the 280mm disc from A8Q - less hassle than spinning down the B7/8E0 300mm disc to work with A8/S8 280mm carrier.
                  Paul Nugent
                  Webmaster http://S2central.net
                  Administrator http://S2forum.com

                  1994 S2 Coupe ABY - aka Project Lazarus
                  2001 A6 allroad 2.5TDi - family tank
                  2003 S4 Avant 4.2 V8 - daily burble

                  Purveyor of HomeFries and Exclusive agent for Samco hose kits (S2/RS2)

                  There are only 10 kinds of people that understand binary - those that do, and those that don't

                  Comment


                  • #10
                    We need a friendly parts man to order some of these by accident and measure them ;-)
                    Paul Nugent
                    Webmaster http://S2central.net
                    Administrator http://S2forum.com

                    1994 S2 Coupe ABY - aka Project Lazarus
                    2001 A6 allroad 2.5TDi - family tank
                    2003 S4 Avant 4.2 V8 - daily burble

                    Purveyor of HomeFries and Exclusive agent for Samco hose kits (S2/RS2)

                    There are only 10 kinds of people that understand binary - those that do, and those that don't

                    Comment


                    • #11
                      Wouldn't GSF do the same one?

                      Anyone on here work for them??

                      sigpic

                      New S2 - S8 & RS2 -RS6 Keyrings

                      Comment


                      • #12
                        Originally posted by S2central.net View Post
                        We need a friendly parts man to order some of these by accident and measure them ;-)
                        Looks like I'll be getting some discs in for stock

                        Shoot me a list and I'll accidentally order some for measurement purposes

                        Ben
                        the best intentions are fraught with disappointment - gil grissom

                        sigpic
                        1994 ABY Avant - it's getting there

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                        • #13
                          I love it when a plan comes together. Will crosscheck the numbers here an forward you a list by email. If disc height is ~40mm then I am very confident about the A8Q 310 carrier. After that it's easy for B3Q and B4Q as there is a suitable for each (two confirmed cases for B3Q).

                          Remember this is for 5x112 hubs only !
                          Paul Nugent
                          Webmaster http://S2central.net
                          Administrator http://S2forum.com

                          1994 S2 Coupe ABY - aka Project Lazarus
                          2001 A6 allroad 2.5TDi - family tank
                          2003 S4 Avant 4.2 V8 - daily burble

                          Purveyor of HomeFries and Exclusive agent for Samco hose kits (S2/RS2)

                          There are only 10 kinds of people that understand binary - those that do, and those that don't

                          Comment


                          • #14
                            Check on here:-

                            http://www.brakeparts.co.uk/

                            They have drawings and dimensions for all the discs they sell.
                            sigpic
                            1991 Audi S2 3B - 2.5 Stroker engine
                            1997 A6 2.5TDi quattro avant - C4
                            1976 RD250E / 350LC cafe racer

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                            • #15
                              I found dimensional info from the ATE on line catalog...

                              A8 310x22 disc has same centre hole as S2 at 68mm
                              Total disc height is 42.4mm which places it a touch further inboard than 40mm height of S2 rear disc

                              The A8 280x22 disc is ~46mm high which isn't important other than remember that we know a ~3mm spacer is required on 280mm A8 carrier when working with 8E0 disc with a height of ~36mm to place it nice and centrally around the disc.

                              So here's my thinking... if the A8 280mm carrier is sized for hat of ~46mm, then with a disc of ~42mm height it is fair to assume the carrier will want to sit 4mm further inboard which is almost the same as removing the ~3mm spacers we know are needed on the S2 application... so by my reckoning it is so close that only a minor tweak should accomodate things.

                              I've asked Ben to order up some bits for measurement and/or dry fit so lets hope that reality matches the theory here.
                              Paul Nugent
                              Webmaster http://S2central.net
                              Administrator http://S2forum.com

                              1994 S2 Coupe ABY - aka Project Lazarus
                              2001 A6 allroad 2.5TDi - family tank
                              2003 S4 Avant 4.2 V8 - daily burble

                              Purveyor of HomeFries and Exclusive agent for Samco hose kits (S2/RS2)

                              There are only 10 kinds of people that understand binary - those that do, and those that don't

                              Comment

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