Mx-5 sill repair

  1. Matt2223 Member

    Messages:
    30
    Location:
    England March
    afternoon folks, can someone give me any tips and advice on repairing this piece of
    Sill on a mx-5. It’s the wheel arch end I’m unsure about.
     
    • 03C0374B-57FE-4D1E-A745-53CCDAC3E604.jpeg
    • AF2B8EF8-F1D8-4BFF-A928-DB3B4E8DC22D.jpeg
  2. rtcosic

    rtcosic Member

    There are three layers at that point. All three will require repair.

    1. The outer layer is part of the rear wing, finishing in the vertical join line under the rear of the door. The crease or join line appears to have been filled with body filler in your photograph.
    2. The next layer is part of the outer sill. It is slightly recessed and passes under the rear wing
    3. The final innermost layer is the vertical closer of the inner wing and a stiffener triangle thing.

    You will need to cut the outer wing well above the level you have cleaned and probably to just below the line of the stone chip to get back to sound metal and gain access to the other two layers. Then drill out the spot welds along the wheel arch, inside the door aperture, along the vertical join line under all the filler and finally the bottom flange to peel it away.

    A repair panel for that part of outer wing is readily available. If you plan to patch rather than replace the sill you will need to fabricate a repair panel, but as it is not visible that's not too difficult a hammer form compound curve job.

    The vertical part of the inner wing is pretty much a simple single curve repair patch from memory, but with a curved flange at the bottom. Again not too difficult to bash out a repair.

    Any of the UK MX-5 forums will have extensive guides to the process.

    Previous post here as well.

    If you get totally stuck we have some photos somewhere of doing this on an NA and NB - which seemed exactly the same BiW to us.

    When you have done fill the sill with cavity wax from inside the hood stowage area.

    Found some posts one or other of the offspring made:
    http://www.phoenixfives.org.uk/forum/viewtopic.php?p=31129#31129
     
    Last edited: Jul 27, 2019
  3. Pigeon_Droppings2 Member

    Messages:
    1,849
    Location:
    london
    If you mean making the lip...a shrinker would do it. First one I did I just cut and welded up...shrinker would be neater.
     
  4. rtcosic

    rtcosic Member

    Ah - I've misread that haven't I.

    I did it by a combination of tucking/shrinking and cutting/welding - as I still haven't mastered tucking/shrinking.

    A skim of filler hides a multitude of sins.
     
    stuvy likes this.
  5. Pigeon_Droppings2 Member

    Messages:
    1,849
    Location:
    london
    Yea tucking didn't work for me...I made one of those forks but it just made a mess.

    Was still a good description of what was needed I thought :clapping:
     
  6. rtcosic

    rtcosic Member

    I just hacksawed a slot into the end of a 1/4"bolt - which is possibly why it wasn't a huge success!
     
    slim_boy_fat likes this.
  7. optima21 Forum Supporter

    Messages:
    2,598
    Location:
    halifax, England
    I've recently tried tuck shrinking with fork and had limited success, but gave up as the amount of hammering was causing havoc with my joints.

    with tucking forks on steel I couldnt get the tucks to be as pronounced as the ones on the eastwood page

    DSC01951.JPG

    I'd then hammer the tuck down from the open end

    DSC01956.JPG

    and the work towards the centre of the tuck. if you work from the centre out, there is more chance of just flattening the tuck. by closing the end first the tuck tuck is still there so the metal has to shrink. well thats how I think it works.
     
    Wonderweaver, rtcosic and decca like this.
  8. Matt2223 Member

    Messages:
    30
    Location:
    England March
    Thanks for the advice. Today was just a quick prod about to see what was there. Just to the left it’s had a hideous patch stuck on top of the sill. I’ll cut that out aswell. I have a feeling I’m going to find a lot of filler.
     
  9. PhillipM

    PhillipM Member

    Messages:
    1,801
    Rotherham
    I just make mine with a vice and a sandbag, the lip is small enough you don't need to go to much effort to form it anyway.
     
    stuvy likes this.
  10. Matt2223 Member

    Messages:
    30
    Location:
    England March
    Now I’ve looked at it a bit closer I see what you mean by the outer is wing covering the outer sill. I see the spot welds underneath the wing but surely I shouldn’t be able to just peel the bottom of it up? Should it not be welded to the vertical lip?
     
  11. Pigeon_Droppings2 Member

    Messages:
    1,849
    Location:
    london
    Looking at the repair panels on sale I think it's just spot welded in....the repair panels don't have a flange?

    Fleabay seems to be awash with repair panels for the MX5...might be easier to just buy them (they look pretty cheap too)
     
  12. rtcosic

    rtcosic Member

    The other spot welds:
    • wheel arch lip or return edge
    • vertical edge on the sill
    • the door reveal
    Apart from the vertical one on the sill which is probably covered in filler in your example, they should all reveal themselves after vigorous wire brushing.

    Or: cut vertically just behind the back edge of the door as shown in the thread I linked to. You should be able to work it out then, as everything should be visible.

    The repair panel we used had a return around the door reveal. Others may not, as Pigeon Droppings advised.

    I'm not sure what you mean by the vertical lip.
     
  13. owas

    owas Member

    Messages:
    1,479
    Location:
    Birmingham
     
  14. Bluemotion

    Bluemotion Member

    Messages:
    47
    Location:
    Holmfirth
    I repaired a few of these over the years. Some pics to help... 1F9A8DA0-611F-4D91-B3AC-BA17FB381AB6.jpeg 1DA8372B-B655-4D09-AC48-3CC8E3495179.jpeg 5A7BDDBD-83E7-4EAE-AA65-847D265124BC.jpeg 14609D4B-6A64-41A2-AC27-9596612F2D36.jpeg
     
  15. NedHan79 Member

    Messages:
    55
    Location:
    Antrim Ireland
    Looks great. Nice and tidy
     
    stuvy likes this.
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