John Deere 650H LGP C-frame repair advice

Hello everyone, hoping for some advice on some C-frame repair that I need to do again. First time I observed crack that was starting on c-frame, got a nephew to weld some 1/2" plate in hope to reinforce and prevent further running of crack, however, after a few jobs, seems that existing crack is creating enough stress that it broke his welds. At first glance, I was thinking maybe that we should have arc gouged a bit where welding bead is to form for better penetration, however, I'm double guessing the way we mounted plate to begin with, perhaps support differently. Any advice is greatly appreciated and if you have pictures, that would be awesome, Thanks again.

crack needs to be gouged out and welded the plate that was welded looks like it has no pentation

I agree with Dave. the crack needs to be welded before you put the plate on or its just going to crack again.

Dave Neubert said:

crack needs to be gouged out and welded the plate that was welded looks like it has no pentation

Click to expand...

As the others mentioned the crack on the side plate and the welds on the inner sides need to be ground out and drill the ends of the weld cracks 1/4" - 5/16" bit. Also all the paint and rust needs to to be ground off in the areas needing welding.
Weld it up then grind the side plates flush. Chamfer the mating edge of the fish plate before welding them on.
Just my .02 worth

That is a bad crack, like the other guys said it needs to be ground out real good, cleaned well, and then welded. It is going to take more than a pass with a MIG welder though. Probably four or five passes.
The welding job with the fish plate had almost no penetration, basically just glued the plate on.

As others have said, no penetration and insufficient prep work. Here is a picture of a proper fishplate repair. Not my work, just a google image.

And preheat before welding and maybe some post heat for stress-relief and also maybe someone with better welding skills