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Welding A Subframe


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#1 DJC MINI

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Posted 13 January 2018 - 08:37 PM

Hi all,

 

My mini has a very small hole in the rear subframe. Its not structural. I've heard welding a subframe can mean it fails an MOT. Is this true? If so will it be best if I buy a new subframe?

 

Thanks,

 

Daniel



#2 sonikk4

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Posted 13 January 2018 - 09:14 PM

A subframe is structural in itself, however if you do a decent enough repair to make it look original then you will be fine.



#3 dyshipfakta

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Posted 13 January 2018 - 09:39 PM

Small holes will become larger though and best not to just scab a plate over it.

#4 robminibcy

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Posted 13 January 2018 - 10:01 PM

not sure where 'welding subframes fails mot' has come from though I've heard it before. A hole of any sort in a subframe is structural so should fail mot though but provided its done properly there's no issue welding it. They are welded together originally anyway! Other thing to consider as well is that its likely there's more rust lurking inside the box sections so whilst a weld repair will get you a few more years id consider replacing it at some point with a brand new one if nothing else for peace of mind 



#5 rkde

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Posted 13 January 2018 - 11:24 PM

I jig and weld subframes. Done it several times, if the jobs done correctly there will be no issues nor any way the MOT garage would spot it. They come from the factory welded...

As others say that hole will be a lot bigger by the time you have repaired it or should I say cut the rot out. I have a box section jig to hold it correctly while I cut out the layers - In time it probably costs me more in my time than it would do to go out and buy a new frame...



#6 minimans

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Posted 14 January 2018 - 02:51 AM

I welded two small patches to mine on the 1960 as they were the original frames, just make sure you dig out all the rust from the panel your repairing and treat with rust converter before closing it all up.

Attached File  mini subframe.JPG   47.05K   4 downloads

Attached File  mini subframe2.JPG   68.56K   2 downloads



#7 The B team

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Posted 03 March 2018 - 03:27 PM

Hi guys sorry to hijack the thread a little but this is the most appropriate I have found, I'm just starting to rebuild my rear subframe and the thread stripped on one of the rear mounting pins, in the last picture its the bottom left and right corner from the previous post, as these parts are welded in to the subframe anyone know the best way to get around it? I was thinking of cutting the threaded part off and drilling/tapping in to the pin screwing in a bolt and cutting the head off, anyone think this is a bad idea/will make it weak?

 

any suggestions more than welcome!



#8 dyshipfakta

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Posted 03 March 2018 - 03:51 PM

I think I would weld one in off of a dead frame. See if someone will chop that section out of a rotten frame for you.

#9 AndyR

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Posted 03 March 2018 - 04:22 PM

Hi guys sorry to hijack the thread a little but this is the most appropriate I have found, I'm just starting to rebuild my rear subframe and the thread stripped on one of the rear mounting pins, in the last picture its the bottom left and right corner from the previous post, as these parts are welded in to the subframe anyone know the best way to get around it? I was thinking of cutting the threaded part off and drilling/tapping in to the pin screwing in a bolt and cutting the head off, anyone think this is a bad idea/will make it weak?

 

any suggestions more than welcome!

 



#10 CityEPete

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Posted 03 March 2018 - 07:35 PM

Screenshot_2018-03-03-19-31-25.png

I've been sorting this today, the rest of the frame is sound, I think it's where the paint has chipped off from people jacking it up. I was changing the rear knuckles and I've rust converted and painted the frame,I'll coat it in waxoyl when the weather warms up.

Screenshot_2018-03-03-19-31-11.png

Cut out the whole end section and butt/puddle welded a piece in after rust treating and weld thru priming everything. Can't see the mot man failing that?

Edited by CityEPete, 03 March 2018 - 07:38 PM.


#11 The B team

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Posted 04 March 2018 - 04:43 PM

Thanks for the suggestions, annoyingly the subframe is all ready powder coated and the person that sent them off never took the brackets off, no idea why, there is a section of thread nearer the pin that is still good so I now plan to run a die down to that piece, build up the end with weld and grind it down to a suitable size then cut it from the inside out with the die as the thread isn't supporting anything just holding the bush in place unlike the pin needing strength, if not then ill have to resort to cutting it out, just trying to avoid destroying the paint at the mo  O_O  

 

If it works ill post photos of the results!



#12 CityEPete

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Posted 05 March 2018 - 10:26 AM

Good luck

#13 docka

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Posted 05 March 2018 - 01:01 PM

What rust converter are you guys using?



#14 CityEPete

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Posted 05 March 2018 - 01:55 PM

I still like Kurust, I grind, sand and wire wheel as much as possible then cover in kurust and leave it to dry then wire brush again before coating in smoothrite, I'll then spray and brush on waxoyl.




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