20 replies to this topic

[Jake Didsbury]

Hello everyone,

Im currently in the process of repairing some holes in the corners of the heel board around the rear subframe mounts. I got two repair panels for each side however they are not heritage ones, and they dont come with the full mounting bracket on them that sits behind the heel board inside the sill. The panels I have only have two holes with a nut welded at the back of each hole.

I would like to know if plating this panel over the top of the old heel board corner section would be sufficient to do the job, or should the old heel board be cut out and weld the new plate in and weld it to the existing subframe mounting braket, the reason for me asking this is because I am unsure if this plate with the two nuts on is strong enough to cope with the stress's and loads the mount will be subject to, as I know the original one is an actual bracket with threaded holes in it, that is not only fixed to the heel board but the the inner sill aswell. If I was to just put this new plate on, it wouldnt be fixed to the old bracket (therfore not having the stength of being fixed to the inner sill aswell, only the heel board) - if that makes sense? haha

Im really unsure, my gut feeling tells me its not strong enough that way.

Sorry thats long winded but i needed to make it clear what I ment, thanks :)
Jake

Edited by Jake Didsbury, 11 January 2012 - 11:50 PM.

[corrado vr6]

Assuming your repairing these corners due to rust in which case it's best you cut out the rusted section or you will actually trap moisture in and make it rust quicker!

If you need to use the panel you have could you not weld in the bracket that joins to the inner sill to help stiffern it up. Ie cut a plate out of some sheet metal to the same size as the original plate that was spot welded to the inner sill and weld it to the panel you have bought once fitted weld it to the inner sill?

[Jake Didsbury]

Assuming your repairing these corners due to rust in which case it's best you cut out the rusted section or you will actually trap moisture in and make it rust quicker!

If you need to use the panel you have could you not weld in the bracket that joins to the inner sill to help stiffern it up. Ie cut a plate out of some sheet metal to the same size as the original plate that was spot welded to the inner sill and weld it to the panel you have bought once fitted weld it to the inner sill?

The bracket itself is intact its only that heel board plate that goes over it thats rusted away, but like you said logic would say to cut the rust out, if I was to cut around the bracket leaving it still fixed on (as it would be holding on via its fixing to the sill) I would be able to fit the new panel ov the top and line the holes up?

[tiger99]

You most likely do need that bracket, but the only way of proving it conclusively is to drive the car without it till something breaks. Some will tell you it does not matter, but it is there for a reason, and unless they are properly qualified and have carried out a stress analysis, their opinions may not be correct.

I would be inclined to recreate the bracket somehow. Note that it should have a stiffening rib. You could make a very strong but simple alternative by using 3 pieces of 2mm approx steel, one inside the heelboard to carry the two nuts, the other, which should be tapered and with a rtounded point like the original to avoid stress concentration on the inner sill. The Somerford web site has some pictures which will give sufficient idea of the overall size and shape if the original is well rusted. These 2 bits get welded together at right angles, or if you can bend the metal effectively, make them from one piece. Then a triangular piece is welded in horizontally to simulate the stiffening rib, about midway bewteen the bolts.

The bracket is the easy bit. Nice, thick, clean, new metal, and thick enough so that welding is a doddle, even with a cheap arc welder. But how do you weld it to the unner sill? Plug weld it through the inner sill, working under the rear seat base, very awkward? Or remove a piece of the ouiter sill? Last time I did one, I cut a piece of the outer sill away, made a new piece and butt welded it in afterwards.

[jmac201]

Reviving an old thread here,  Im replacing the same section of the heel board.  My question is the nut threads.  Are they different than the orginal, because the bolts I have are not threading in easy and I dont want to replace with the panel and have to deal with the issue of trying to mount up the subframe and stripping out the nuts later on

 

Jeremy

[colinu]

I replace my heel board ends with Hadrian ones recently, They used the same bolt thread/size as the original panel (5/16" UNF???)

[jmac201]

When I start the thread the bolts in, it offers quite a bit of resistance so I've only went in mabye 1.5 threads. Once I backed the bolt out it has some evidence of cross threading almost like its UNC instead of UNF.  Could this just be the coatings within the thread and it working its way off?  these are the panels from minispares

[sonikk4]

They maybe metric captive nuts installed. This has happened before. Normally they are if memory serves me correctly UNF.

[jmac201]

Went out this evening and attempted to "persuade" the bolt,  Yeah the bolt and nut are different threads, now its just spinning and tore the bolt threads to crap.  I saw a thread once where someone just drilled and tapped a block of steel, does anyone remember seeing that one? 

 

Jeremy

[jmac201]

They maybe metric captive nuts installed. This has happened before. Normally they are if memory serves me correctly UNF.

I think my repair panel is UNC, sucks they don't match.  I paid more in shipping to get that little piece to Germany than the piece itself

Edited by jmac201, 19 July 2013 - 06:18 PM.

[tiger99]

It is wrong, but unlikely to be UNC, far more likely to be M8. Under no circumstances try to retap it, as that will leave it hopelessly weak. You could try M8 bolts but make sure that they are marked 8.8, not an inferior grade.

[jmac201]

It is wrong, but unlikely to be UNC, far more likely to be M8. Under no circumstances try to retap it, as that will leave it hopelessly weak. You could try M8 bolts but make sure that they are marked 8.8, not an inferior grade.

My plan is not to re-tap the current crappy nuts, but to drill/tap a hardened steel piece and weld it in, or weld in a two nuts that is high tensile strength that have the right threads.  I have spare brand new trunnion bolts (SH605181) from minispares and they will not thread in either.  arghh! I'm not buying any pattern parts again.  I am going to hit the store tomorrow with the panel and see if I can find a correct fitting/rated bolt

[alex-95]

I think you are talking about mine, From post #82

http://www.theminifo...-rebuild/page-6

[jmac201]

I think you are talking about mine, From post #82

http://www.theminifo...-rebuild/page-6

Thanks!  That's the one I was thinking of.  Did everything work out alright, still holding good?

[alex-95]

 

I think you are talking about mine, From post #82

http://www.theminifo...-rebuild/page-6

Thanks!  That's the one I was thinking of.  Did everything work out alright, still holding good?

 

Thats alright, I still haven't had the subframe back on, but I'm sure it'll be fine.