Cracked Frame

Hey guys,
I have read a quite a few posts on this subject and was looking for feedback on my situation. I was cleaning up my 73 frame and discovered this crack just behing the shock mound stud and before the motor mount brackets. I understand I need to drill out the cracks to stop them and then weld back in, as well as reinforce the with fish plates. Do you guys have these plates fabbed for you? The problem is my crack is on the up slope of the frame so any plate in weld in will have to be short because of the curviture of the frame. Please any help would be nice. Wind is kinda out of my sails at this point.... Heres some pics. let me know what you think. Thanks guys.

 

I'm certainly not an expert on this subject, but if it was me, I'd drill the holes at the crack ends, V out the rest of the crack then just weld it in. You could add a plate to the flat side to reinforce it some more. That's just my thoughts, I'm sure others more qualified will jump in.:?

 

This seems to be a standard problem My 75 cracked pretty much in the same area only on the bottom and back in two different places.. I ground the crack out a bit, welded the crack itself closed, ground it flat and then added a piece of like 3/16" plate that I made over the top.. I only weld the plate it up in the horizontal direction. Mine went around the curve as well, I just used two plates, one on the side and one on the bottom..

In your case, I'd unbolt that brake line and go from there..

 

Just did this with my 74. The frame cracked behind the spring hanger, it started on the bottom of the frame and was working it's way up the side. I ground it out and stop drilled the crack then had it TIG'd. Finally added a fish plate that I fabricated out of 3/16" angle.

 

I would start by removing the paint and find the end of each crack. Then drill a 1/8 or 1/4 inch hole at each end, this will help stop the crack from growing. Then use a grinder or cut off wheel and grind along the entire crack. You don't necessarily need to grind all the way through the crack, but you can. The purpose here is to remove contaniments and to allow better penetration when welding. Weld the crack and the holes. What you do next is up to you, but I don't always put a plate over every crack. The idea with a plate is to double the thickness of the area around the crack and strengthen it. A fish plate or similar design can be made with 1/8 or 3/16 inch plate easily. You can also make a diamond shape plate to cover the cracks. If the plate is not done correctly the crack will return, not necessarily in the same spot, but along a shear point between the old and new metal. IMHO if the weld repair holds then leave it be without a plate, if the crack continues to occur then add a plate.
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Thanks for everyones help. I thought I was kinda on the right track but you guys confirmed it. Luckily I have an experienced welder here at work that will help me out with the welding aspect of it. I will post some pics of the finished product. You guys are awesome!
Thanks
Steve

 

Have recovered several cracks in my frame as well... putting my plasma cutter and mig-welder to some good use recently... But, do suggest a good overview of the "Jeep Rebuilders Manual" for further insight on Jeep Frame repair(s). Although reworking is something I thoroughly enjoy... I never get enough of the different ways a Professional Welder" can repair a crack and in the end... the area repaired is always stronger when "good penetration" has been accomplished in the repair! All the best with your restoration of the cracked area... looking forward to some images!

Semper Fi!
Gunner