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Thread: Adapters to mount a Rear Euro Bumper on a USA spec e21

  1. #1
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    Adapters to mount a Rear Euro Bumper on a USA spec e21

    This thread shows the brackets/adapters I had made up to attach a rear european bumper to a USA-spec e21's bumper shock mounting points. McFarland Performance used to make a nice bracket that bolted directly to the sheet metal of a USA valance, but required drilling new holes in the valance. Unfortunately, I don't think he's still making them.

    These that I made bolt onto the existing USA bumper shock mounting points brackets and don't require any new drilling in this rust susceptible area.

    I am attaching a PDF of my drawing that probably won't print to scale, so rely on the dimensions rather than the actual size of the drawing. Scroll down to the bottom of this post for the PDF. I got my local machine shop to make the adapters from a cardboard template I made.

    I used 1/8" thick steel and powdercoated them after all the fabrication was finished. Remember that these have to be used in conjunction with the OEM brackets that attach to the euro bumper. My adapters just supply the mounting points for the OEM euro brackets:

    Shown above are the OEM brackets that would normally bolt up directly to the european model's sheet metal. The adapters I had made bolt up to the brackets using those captured nuts.




    The USA bumper shock mounting has two holes (one threaded) that provide convenient points for my adapters to be attached with a couple of bolts.





    You will need two of these adapters, one for each bumper shock mounting location and they will be mirrored. In other words, the 90 degree angles go in opposite directions. Refer to the photos to help visualize what's needed. The drilled holes are 5/16" diameter. The slotted holes are 5/16" x 3/4". Here's the process:
    1. Cut the overall shapes out of 1/8" thick steel (4 pieces total)
    2. drill and slot the holes
    3. Weld each pair of pieces at 90 degrees (mirrored) to make the two adapters
    4. Powdercoat or paint the fabricated adapters
    5. Attach them to the bumper shock points with stainless and aluminum hardware
    6. Mount the euro bumper (and OEM brackets) to the fabricated adapters with stainless hardware

    The drawing in the attached PDF (at the bottom of this post) is trimmer than the bracket adapters that are shown in the photos. They don't need to be as wide unless you are also using some sort of rear skirt/valance covering the area below the bumper like the Zender skirt I am using here. If you don't have a rear skirt under the bumper, the larger brackets will be visible from a low angle. That's why I redesigned them to be smaller (see the attached PDF) for bumper only conversions.



    In the photo above, you can see that the upper bolt is much longer than the lower one and I used an aluminum spacer tube that positions the adapter in a vertical orientation. I don't remember the length of the spacer tube and it's hard to get in there and measure it with the rear skirt covering everything. I'm afraid you're on your own for figuring the exact length of the spacer.



    I hope this is clear. Let me know if you need more info.
    Attached Files Attached Files
    Last edited by dumbclub; 07-03-2017 at 08:25 AM.

  2. #2
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    First I must say you did a really nice job. Second, my son has an 81 and is really looking forward to installing euro bumpers on the car so this is a great help.
    Thanks for posting!

    BTW, your car is beautiful.
    'Simplex sigillum veri'

  3. #3
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    Dude!! Thank you so much for this writeup and template. I am sure it will benefit a lot of legionnaires including myself. Thanks again! Your car is outstanding by the way!

    Also, If you want to print these to scale, set printer to Landscape and set the scale to 142%. It will print on 8.5x11 and be usuable to trace out on your sheet steel.
    Last edited by bassboy3313; 10-25-2012 at 09:59 AM.
    1999 Z3 Coupe 2.8L


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  4. #4
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    OR .....

    Just use the pdf that I attached below. I took the original pdf, resaved it to the correct scale. So just open it up and print like normal and you will have dumbclub's template in the correct scale. Hope that ok dumbclub. Thanks again!!
    Attached Files Attached Files
    1999 Z3 Coupe 2.8L


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  5. #5
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    Quote Originally Posted by bassboy3313 View Post
    OR .....

    I took the original pdf, resaved it to the correct scale. So just open it up and print like normal and you will have dumbclub's template in the correct scale. Hope that ok dumbclub.
    Thanks bassboy!
    That is absolutely OK. I was hoping somebody could figure out a way to do that.

  6. #6
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    a littler interpolation solves most issues. :P
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  7. #7
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    The template works! Just need to slot those holes and I am in business. Now to find a set of euro bumpers. Gah!! :P

    1999 Z3 Coupe 2.8L


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  8. #8
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    You car is very nice.

    Alpina diff cover!


  9. #9
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    Amazing Thank you dumbclub

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    nice work all

  11. #11
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    GGray is offline Did someone say racetrack BMW CCA Member
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    Wow that's cool.

    I like the body colored bumpers to.
    Gary Gray



    If you can take it apart you can make it faster!

  12. #12
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    Thanks everyone. I'm glad that the info is helpful and it looks like bassboy's adapters turned out great - just slot 'em, clean 'em up, and paint 'em.

    I think the body colored bumpers are a good practical alternative to refinishing them in chrome. You don't have to be as meticulous with the straightening and foundation work when you are painting. The metal work has to be flawless when you rechrome because even the tiniest imperfections are magnified by the chromed surface. When you paint them, you only need to be proficient with good basic bodywork and painting techniques. Plus you can do the whole job in-house.

  13. #13
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    Quote Originally Posted by dumbclub View Post



    I hope this is clear. Let me know if you need more info.
    And there it is again.. wow, looks good. perfect execution.

    '81 320i turbo | t25, 931 CIS, 240hp, 13.92@100mph | 2.2L m10 Turbo Build | My E21 Videos |

  14. #14
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    first off, it's late and I have had a few beers.
    dumbclub you have a beautiful car and good work making theis brackets, Thanks for the link. Is that a wood shop? So clean!!
    Bassboy did you make thoughts brackets? Good job and on the PDF.
    jr new rims? I like!!

  15. #15
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    I am sure it will benefit a lot of legionnaires including myself.
    Last edited by princwendt; 12-05-2012 at 09:08 AM.

  16. #16
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    Quote Originally Posted by bmac320i View Post
    first off, it's late and I have had a few beers.
    dumbclub you have a beautiful car and good work making theis brackets, Thanks for the link. Is that a wood shop? So clean!!
    Bassboy did you make thoughts brackets? Good job and on the PDF.
    jr new rims? I like!!
    Yes I did and thank you very much! Figured it would help everybody out so they wouldnt have to fool around with the scaling. Enjoy!!!
    1999 Z3 Coupe 2.8L


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  17. #17
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    the bracket is very helpful. thank you. i was wondering if there was a diy bracket for the front bumper?

  18. #18
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    The front bracket is much more straightforward because it bolts to holes that are already in place on the US model's frame rails, just inside the engine compartment and they are easy to get to. They can be made from simple bar stock.

    The only problem with the front brackets is the odd angle that they are bent. Your best bet would be to find a pair you can borrow and match them. Of course, it's not that easy to find a set that's not already on someone's car. An alternative method: you could make some cardboard templates, mount them to your frame rails and experiment with bends until you get them to line up with the holes in the bumper's center section. An extra set of hands would be invaluable for this.

    They aren't numbered in this diagram, but here's what they look like:

    Last edited by dumbclub; 06-03-2015 at 07:31 PM.

  19. #19
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    I made the ones bassboy designed.

  20. #20
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    is the template to this still floating around? the attach file is not opening

  21. #21
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    Both Dave's (bassboy3313) and mine open when I click on them, but that may be because I had downloaded them previously.

    Let's see if this new attachment works for you:
    bumper bracket adapter.pdf

  22. #22
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    Properly dimensioned drawings? That's my fetish.

    Thanks for the drawings!
    -John

  23. #23
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    Reviving an old thread here. Seems like the pic links are broken.
    Trying to think through install. The euro bumpers I found have home made adapters.
    Cant figure out how they align though.

  24. #24
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    Shoot me your email by PM and I'll send you the whole thread in pdf form. This thread works for me with Chrome's photobucket fix, but if you're not using chrome that's no use to you
    -John

  25. #25
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    Install this will fix the broken links.

    https://addons.mozilla.org/en-US/fir...-embedded-fix/
    (this is for firefox)

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