Fino's 1970 Mini Build Thread

I don't think so - at least not the section along the shock mount. The crack ran along the radius edge, and the top flange as it looks like the OEM rivets were ripped through it - or someone blasted them out with a torch. So the frame section is in two pieces that I'd have to weld back together. I think a complete 1piece section replacement is the only way to go on this one - but what do I know? The front section at the spring hanger maybe something I could re-use....after removing the spring hanger, I may be able to weld the crack up in place (after grinding it out clean etc), and then plate over it without having to remove a section of frame.....in this case, the crack run perpendicular to the frame so its not as complicated as the shock mount that ran parallel to the frame and along the radius. Not always sure when to do what

So, how important is it to use a somewhat matching radius for the repair....on the frame horns, Chuck harvested a section of C-chanel frame rail from an old trailer or whatnot that mostly matched. I on the other hand, don't have anything with that sort of pressed channel edge shape. I could use angle iron and grind the outer edge roundish and blend it in to the surrounding rail, but that is mostly aesthetic, and would probably still create a significant disparity between the welded sections (disparity meaning increased stress concentration and more likelyhood of cracking again).
Another option would be to buy a section of either C-channel or rectangular tubing from metal supplier that is as close as i can get to matching the frame rail (in terms of thickness and edge radius), and harvest from there.....
Or, yes I could take jeep peep up on frame section offer....

 

A couple questions/thoughts before I get too far along:
1) Regarding welding the spring hanger crack - my plan would be just to clean up/grind out and weld the crack, not cut out a section like I did on the rear shock mount. The crack goes under the back edge of the spring hanger, so welding it up from the outside/underside of the frame is not possible. It would be possible to weld the crack from inside the frame rail on the passenger side (not so much on the driver side with the other stuff in the way - see below). I am thinking the best way to do this is to remove the spring hangers, weld up the cracks from the ouside/underside, fishplate the outside, and weld the hangers back on with a section of fishplate between them and the bottom flange of the frame rail - sort of like duffer shows:

I made butterfly plates out of 1/2" plate to fit between the frame and the hangers to spread the loading out and provide more weld area. With the Holbrooks, all that had to be moved anyway. The front hangers are just the stock hangers both bolted and welded to those plates. The rear hangers are entirely custom welded to those plates.



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johnd · Sep 4, 2023 at 11:22 AM

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My first thoughts are that its a bit of a PITA to get the spring hangers off - and even with the leafs unbolted from the hangers, I am probably going to need to pull the entire leaf spring from the axle or disconnect the axle from the frame and slide the whole thing forward and out of the way.....that really isn't too bad - some shocks, driveshaft, brake lines and steering linkage at the bellcrank.....

2) I found a 3rd crack at the driver side front spring hanger just the same as the one on the passenger side - the crack goes under the spring hanger just like the other side, so it would be the same process as above:


the challenge with this one is access to the inside of the frame rail is not good - the ross box and MC and a bunch of brake lines are immediately in that area.


The bit issue with this area, there is no way to box in the frame with the ross and MC sitting tucked in the channel.....Guess I'd just have to go with it and know that it will make it less durable? I can box it in if I ever go to saggy box - at least up to the point of the MC?

And just to show....I ground the rear shock mount free from the frame piece I cut out....the frame section in there was pretty bad, so it all had to come out and a new section gets welded in....

 

I'll take you up on the offer....PM coming for details.....

 

Definitely is not....the MC and pedal cross shaft support sits behind the Ross and sits inside the frame. The frame is boxed from the front cross member to the Ross box, but not past. Not the best pic, but it's open behind the Ross all the way to the tail

 

That is the same....you can see that right behind the Ross mount the frame is not boxed - the boxing cuts down at an angle (to disperse stress, avoid stress concentration), but that leaves the back half of the spring hanger without boxing above it...that is the exact spot I am getting cracks....

 

ok - i see what you mean....we just had different meaning for the word 'behind' vs further aft/rearward.....all good....

no way I am boxing this frame entirely as is! I think at this point, even if I ever did a frame off, I'd just replace the frame with a TDK or something as opposed to trying to salvage this one and box it. If my repairs can buy me a few more good years, it'll owe me nothing....

 

Well, as i mentioned above, I just really feel like to get good repair on the spring hanger cracks, I really need to remove the spring hanger as the crack is under them. That required getting the leaf spring and axle out of the way:


And then I finally got the passenger spring hanger cut-off....full crack in view and ready to be cleaned up and welded.....


unfortunately I trashed the spring hanger getting it off, so I guess I'll have to order a new one. Now I've got to see if I need to order two of them depending on whether I can get the passenger one off without wasting it. Frustrating to waste that piece, but I don't think they are all that expensive.....I guess this is progress....gotta tear it apart before you can repair and get it back together....