Crack in frame....!

Digging deeper into the 70 I just picked up, I discovered an older repair. The frame was torn on the bottom, just about where the steering box is. the crack went up the frame rail. The repair was structured by drilling a hole to prevent further cracking and a large piece of flat plate was added to the outside. The crack was not welded. I need some advice on ensuring that this doesn't get any worse. How would you veterans go about fixing this? Pictures forthcoming as soon as I can get them.

 

Hard to tell without pictures. If you search, frame welding comes up a lot in reference to repairs and/or strengthening. These frames often are cracked where the spring hangers attach to the bottom of the channel. If it's cracked back where the Ross box mounts, I don't think that's a very common failure.

Billy posted some good pictures from the Hummer military M&R manual - maybe he can link them again. For a channel frame, my understanding is that welding across the rails is very bad, and welding across the web is not good. Your welds should be along the long axis of the frame. Usually this means a plate or strap that covers the crack, with welds as parallel to the long axis of the frame as possible. Plates usually are not welded on their ends, or have a "fish mouth" cutout to make the welds at a long, shallow angle to the long axis of the rails.

There's some good info at the CJ-3B page: http://www.film.queensu.ca/CJ3B/Tech/Frame.html