Black Triangle Repair

[eddd]

It seems like most Black Triangles suffer a broken post somewhere along the way, and for some reason the left side is the first side to get damaged, probably due in part to the lift handle on that side.

 

My '96 did not have the extra post that snapped into the side tupperware; that post came in later years. It turned out that the '99 I'm parting out had one good side and the other side had lost the post. Using epoxy to reset the broken post doesn't work as those who tried it found out. There was a repair procedure over on BMW MOA, but that one didn't impress me as the best solution. I decided to try and come up with my own procedure.

 

I had the good side to study to see what the end result needed to look like.

 

 

 

 

 

 

The broken side:

 

 

 

The solution was found as I looked through the very extensive fastener section at my local Ace store:

 

 

 

 

The nylon fasteners are 1/4 x 20. The spacer is 1/4" thick and 1/2" diameter. The screw was 1 and 3/4" total or 1 and 1/2" of threads.

 

A little JB KwikWeld will secure the spacer to the screw.

 

 

 

 

I made a few of these today and found it was much easier to secure the rotary tool than the screw. I used a drum sander bit for the removal and the stone bit for polishing.

 

 

 

 

 

The last three pictures are of the same post though the don't look like it. The unexpanded diameter of the grommet on the tupperware is 8mm or 0.320 inch. I ground the head of the post down to 10mm or 0.390 inch on one axis and 8mm or 0.320 inch on the perpendicular axis when viewed from the top of the post. The difference mirrors the original design and allows the post to more easily slide through the grommet. There will be a bit of of grinding and test fitting until you have it right. You'll note the bottom of the head is also rounded to help the post pop back out when you go to remove it. The head measures 9mm or 0.360 from its top to bottom.

 

Use a small drill to ensure you are in the center of the the old post.

 

 

Enlarge that hole to 1/4".

 

 

 

Cut the post to a total length of approximately 36mm or 1.420 inch.

 

Position the post so that the top of the head is 18mm or 0.720 inch above the flat base mounting area. You can get under the mounting surface to help get the post at the correct height. Use some epoxy on the top side to secure it in place.

 

 

Once the epoxy sets on the top add a generous amount to the underside of the mounting surface.

 

 

The repair seems to be very strong, and the dollar cost is minimal, certainly a better option than forking out $80 for a new one.

 

I'll move this down to the DIY section after it spends a little time here.

 

 

Edit: In the original version of this post I suggested that you might want to fill in the threads with epoxy for added strength. I ran some tests today to gauge the strength of the nylon screw in its natural condition. You definitely do not need to do anything to improve the strength of the screw. It is very resistant to breaking even when bent at angles that would not be possible when removing your triangle.

 

 

 

[Huzband]

 

I'll move this down to the DIY section after it spends a little time here.

 

 

Uh huh.

[Dances_With_Wiener_Dogs]

Brilliant! I must try this on mine. Bonus that I actually have the snapped off bit.

 

[mneblett]

Brilliant! I must try this on mine. Bonus that I actually have the snapped off bit.

If you have the snapped off piece, you can try this: I drilled a hole part way down the center axis of the broken off stud from the base side (using a drill press; no way could/would I drill something that small by hand), then drilled a hole in the center of the base, then inserted a screw from the back side of the base through the base hole and into the stud. It is secure enough that I didn't bother with adhesives.

[Alba]

Thanks for the inspiration, any ideas for the locking screw? currently using a bolt

 

[eddd]

Thanks for the inspiration, any ideas for the locking screw? currently using a bolt

 

The replacement parts for that is still available and quite reasonable:

 

link

 

Buying the replacement parts is going to be the way to go.

[smiller]

Epic Ed. I love that kind of stuff.

[biometrics]

Nice job! My only recommendation would be to not use plastic for the repair.

 

I did something similar to your repair shortly after getting my RT-P bike and posted the photo essay here:

 

http://bmwsporttouring.com/ubbthreads/ubbthreads.php?ubb=showflat&Main=64281&Number=715209#Post715209

 

The difference between my repair and yours is that I used brass hardware, and for the tip I used epoxy and a brass acorn nut and then basically reshaped it as you did. I reinforced the installation by filling the well under the stud with 5 minute epoxy and letting that harden.

 

The repair has held up through numerous removals, and I don't worry about it ever breaking off again...

[eddd]

Nice job! My only recommendation would be to not use plastic for the repair.

 

I did something similar to your repair shortly after getting my RT-P bike and posted the photo essay here:

 

http://bmwsporttouring.com/ubbthreads/ubbthreads.php?ubb=showflat&Main=64281&Number=715209#Post715209

 

The difference between my repair and yours is that I used brass hardware, and for the tip I used epoxy and a brass acorn nut and then basically reshaped it as you did. I reinforced the installation by filling the well under the stud with 5 minute epoxy and letting that harden.

 

The repair has held up through numerous removals, and I don't worry about it ever breaking off again...

 

 

Yours is definitely better looking. Something like that should be on the outside not hidden away.

 

From what I can tell so far the nylon should make a strong and permanent repair. I does not have the brittleness of the original piece. In addition, the breaks seem to always be at the flat surface not the peg itself.