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  • #16
    Originally posted by JuhaV View Post
    Olified, if you could perhaps take more pictures from underneath your car it might help to find the problem ?

    Here are some pictures from mine (scroll down to see the rear end subframe related ones) : https://plus.google.com/photos/11351...LXkmuWj46W42wE

    The diff is attached to the subframe with those four bolts from the top. As c_w said, there is not much (if any) play in these and therefore the diff can only have one position in relation to the subframe.

    Then the subframe/diff combination is attached to the car at three locations :
    2 x front subframe bushes + 1 x rear diff bushing.

    This gives us basically the following theoretical places to have an issue :
    1) Front subframe bushes are shot or the bolts in the bottom of the car to hold these are bent -> the whole subframe becomes incorrecty positioned respect to the car body. If you remove the diff bushing bolt, in theory at least, you could bend the front bolts when you bush the subframe downwards ?

    2) The subframe is bent (very unlikely if it came out ok and the car has not been severely crashed ?)

    3) Diff endplate is incorrectly assembled to the diff body (this may not be even possible without having oil leaks ?)

    4) The attachment in the car body for the diff bushing is bent. It is rather thin sheet metal and could happen.

    5) The diff is not correctly attached in the subframe but has incorrect angle respect to the subframe (= tilted respect to the subframe). Cannot recall if there were any shims in between the diff and the subframe but with those you could incorrectly angle the diff in the subframe ?
    Some pics that might help :

    https://v2tre.wordpress.com/2016/03/...d-and-updated/

    https://v2tre.wordpress.com/2014/02/01/pera-irtaallaan/

    https://v2tre.wordpress.com/2014/03/...menna-ajetaan/

    Good luck. Hopefully it is some minor hick up.

    br, JuhaV
    I relation to your comment on the shims, mine had quite large spacers between the subframe and diff on all four bolts

    Build thread: https://www.z3mcoupe.com/forum/showthread.php?t=19347

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    • #17
      Are you sure they weren't just the thick washers that sit on top that the bolts go through? I'm not aware of any spacer/shims between the diff and subframe.

      The washers are 15mm thick, I'm not sure for the reason why they are used; after the 2nd diff change I used E30 bolts which are a larger headed bolt and thinner washers so the bolt head doesn't sit so high up to the boot floor (makes access a little easier).

      http://www.realoem.com/bmw/enUS/show...diagId=33_0531

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      • #18
        Spacer / shim / washer it's all the same to me!

        Build thread: https://www.z3mcoupe.com/forum/showthread.php?t=19347

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        • #19
          Its a bush according to BMW

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          • #20
            No I mean, are you sure they sat under the subframe between the diff and subframe on your car? as they sit on TOP of the subframe and just act like a big washer for the diff bolts (they don't space the diff from the subframe normally). Couldn't see the point in them so I swapped them for thinner washers which mean bolt heads cleared the boot floor/easier to access with a spanner.
            Last edited by c_w; 25-03-2017, 05:12 PM.

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            • #21
              Originally posted by Olified View Post
              Today i checked the subframe. What should i say? Its like on the pictures from the guy with the white Z3M

              So i will buy next week an E30 Subframe to make sure, where the problem is. What ever the previous owner did


              I will keep you up to date !
              the e30 subframe does not bolt to an z3 chassis, only the trailing arms bolt up
              BMW e21 track car
              Z3M (S62)
              2.8 Z3 Coupe
              Ariel Atom
              GT86 race car
              Ferrari 348 Challenge
              Merc G500

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              • #22
                Maybe we talk past each other.

                What iam Talking about is the rear axle carrier. And this is until two details between e30 and Z3 the same Part.

                See:

                http://smg.photobucket.com/user/gizm...34155.jpg.html

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                • #23
                  Silly question I am sure but;

                  Have you checked your boot floor isn't cracked and dropping at the rear?



                  Was the diff bush at the right angle before you did the rebuild?

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                  • #24
                    Its not silly because that was my first thoughts.
                    The boot floor is perfect. Checked a few times.

                    I only have three or four pictures before the rebuild. But iam sure it wasnt right :-(

                    Today i picked the carrier from the E36 compact. This one have got the pins on it which the one from the E300 does not have.

                    This afertoon i will start the rebuilt second time

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                    • #25
                      I once put z3m running gear on an e30 M3, and the z rear beam did not sit properly, so used the e30 one with Z'd trailing arms. From memory the beam bushes are a different size (height)

                      This could cause the beam and hence the diff to sit at an angle and not line up.
                      Last edited by e21jason; 26-03-2017, 03:01 PM.
                      BMW e21 track car
                      Z3M (S62)
                      2.8 Z3 Coupe
                      Ariel Atom
                      GT86 race car
                      Ferrari 348 Challenge
                      Merc G500

                      Comment


                      • #26
                        I once put z3m running gear on an e30 M3, and the z rear beam did not sit properly, so used the e30 one with Z'd trailing arms. From memory the beam bushes are a different size (height)

                        This could cause the beam and hence the diff to sit at an angle and not line up.
                        Yes, youre right. The difference is the height of the attachment on the axle for the trailingarm bushes.

                        But i had measured it and the holes for the screws are in same positions.
                        Hopefully it works. The guy here has done the same:

                        http://www.bmwfanatics.co.za/showthr...d=64543&page=3

                        I will write to him and give you the answear.

                        So my beam is bent, too. Making the "new, old" E36 Compact beam on it and everything is fine... I dont no why the old one is bent. Maybe threre are more Z3M with that problem but the owners dont know ?!
                        Attached Files

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                        • #27
                          Originally posted by Olified View Post
                          Yes, youre right. The difference is the height of the attachment on the axle for the trailingarm bushes.

                          But i had measured it and the holes for the screws are in same positions.
                          Hopefully it works. The guy here has done the same:

                          http://www.bmwfanatics.co.za/showthr...d=64543&page=3

                          I will write to him and give you the answear.

                          So my beam is bent, too. Making the "new, old" E36 Compact beam on it and everything is fine... I dont no why the old one is bent. Maybe threre are more Z3M with that problem but the owners dont know ?!





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                          • #28
                            beam is now sandblasting. Next week i will built up the car again. Without all your help it would not have been possible

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                            • #29
                              Hi Guys,

                              after all iam finish. At the end of the day it was truly a bent beam.
                              The values of the chassis are now perfect. Before it was just terrible.

                              A big thanks to all of you - the tip with the guy from south africa was great beacause his problem was the same like mine.

                              Some important information (maybe someday somebody have the same question):

                              The beam from the E36 compact fits on all Z3 - there are two differences you have to note:

                              1. Exhaust manifold right is missing, of course. (In my case i separated the exhaust manifold from the old beam, measure the E36 Compact beam and welded on it)

                              2. The mountings on the beam are a few mm smaller and the weld on the inside is smaller. Its not really a problem. Solution: reinforced the inside.

                              See Pics for more information.


                              Greats

                              Oliver
                              Attached Files

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                              • #30





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