So my 20 year old step son says he has a problem with some thing being broke under his truck. I heard the tail pipe rattle a few times so.. Wrong.

He shows me a crack in the frame right over the axle. How long ago did that happen? I ask. Ohhh a few months ago. Sigh...

Spent 4 hours doing a frame patch. Shock mount is broke to boot. I did the outside of the frame today. will do the shock and exhaust hanger brackets next weekend.

So I had him do some of the work, Nothing is free. I figure this will hold till next weekend.

I would suggest putting a plate across the weld as well. Otherwise you may be back at it again when it cracks alongside the weld. There was some kind of stress causing it, and I doubt that stress went away, so you want to be sure to not have the weld be the only thing holding.

We posted at about the same time... A full plate would have been better, but that should do the trick.

Fellro said:

I would suggest putting a plate across the weld as well. Otherwise you may be back at it again when it cracks alongside the weld. There was some kind of stress causing it, and I doubt that stress went away, so you want to be sure to not have the weld be the only thing holding.

We posted at about the same time... A full plate would have been better, but that should do the trick.

Click to expand...

I have another plate for the inside of the frame. So yea. I also have to do the top flange of the frame. To tired to deal with it today., That will hold till next weekend.

Fellro said:

I would suggest putting a plate across the weld as well. Otherwise you may be back at it again when it cracks alongside the weld. There was some kind of stress causing it, and I doubt that stress went away, so you want to be sure to not have the weld be the only thing holding.

Click to expand...

X2. I would suggest a doubler made in the shape of a diamond so as to gradually draw the load away from the cracked area. The trouble with a blunt butt weld is twofold in that not only are the residual stresses from the weld of unknown magnitude (conceivably, right at the material yield strength or greater) and any sharp groove/pit is an initiation point for the crack to resurface (stress in it's purest form = force/area, and the area at the bottom of a crack/pit is approaching zero, thus, stress goes through the roof). The idea with the doubler is to take the load away from the failed area and the diamond shape does it gradually rather than abruptly (fatigue and durability concerns resolved with the diamond shape).