A body like that should never be welded on frames need to flex and a weld dont like flexing.

 

I had it mounted like a local shop that builds and sells flat beds and dumps. I just basically copied them. When I put it back on, it will be bolted to the mounts, lesson learned. I am in the process of fixing the cab myselft. I got it pulled back out yesterday and the ripped cab stiched back together. Wed I am going to finish dolling the cab out and start doing some bondo work to get it ready to paint. I will post pics when I can.

 

"Have that bed attached better next time."

Agreed. As you can see in the pic, the frame just tore along the weld down the side if that channel. It for sure going to need to be repaired right there. I'm also surprised to not see any rust behind that channel. The way it was attached, it was a pocket just waiting to trap moisture.

Also, count this a blessing. My BIL used to work at a body shop. They made an awful lot of money by fixing frames with beds and bumpers solidly welded to them. Just the smallest of bumps would rack a frame. The breaking welds actually saved you alot more than your realize.

 

Got the back of the cab stiched up and pulled back out. Gonna start on the bondo work tomorrow.

 

Looks good...

 

lookin good, it will survive

 

Almost ready for primer and paint. Still have to fine sand then prime and wet sand, but getting there.


The back wall under the window in the ribs is not perfect, but it will have a flat bed bolted in front of it so you want see it. I think while I have the headliner and back seat out I will spray with some sound deadner/rubberized coating to maybe quite things down a little.

 

In regards to remounting the flatbed.

I fabricated a 9 foot flatbed for my 2001 Dodge 3500 dually out of rectangular tubing before considering such construction would not flex as would a flatbed constructed from channel and angle.

Although it was a flatbed I mounted it with hinges in the back so if I wanted a dump function all I would have to do to make it a dump is to add a hydraulic cylinder.

Thinking of it as a dump bed also solved the "flex" concerns as dump bodies are not fastened at all in the front. A piece of steel flared outwardly on each side of the frame provides a guide to center the body when the dump comes down and also to keep the body centered in transit.
(Of course a dump cylinder would provide some resistance to body separation in a accident, but not much.)

What I am saying is essentially the front of the flatbed doesn't actually need to be bolted down tightly (as long as the rear mounting is properly designed).

I welded an angle bracket to the flatbed main rails and bolted an opposing angle bracket to the truck frame.
Drilled a 3/4 inch hole through the flats of the bracket and used a 4 inch x 5/8 diameter bolt through valve springs on either side if the bracket secured with heavy washers and a self-locking nut.

The springs are not necessary, just the bolt alone will provide the required frame flexing. The springs keep the bolt centered and eliminate rattle.

When the truck twists on uneven ground you can hear the flatbed rails thumping the frame as the truck becomes straight again.

Some folks say this is all unnecessary, just bolt it down solid.

A friend's truck body is mounted solid and your can actually hear his extended cab squeaking and creaking when the truck flexes.
I visualize all the flex occurring from the bed forward, the front half of the frame taking double the flex. Doesn't seem to be good engineering. I'll err on the side of flex mounting.

 

I might steal your mounting idea because I was considering having it as a dump later also.

 

You're going around the horn just because it was YOUR truck. Get as much as possible from the ins carrier then look for another. Buy this back as a parts truck or go 12V.

 

Insurance said $3900 and estimates were $2200 and $2500. I am fixing it myself and right now am looking at my labor (free), a new back window ($150), and paint($100), so I figure I am gonna come out pretty good considering I only gave $3800 for the truck when I bought it.

 

It looks like the 3" channel is welded to the truck frame and I don't think Chrysler uses any structural steel anywhere on their products. The body installer may have done that but it doesn't make it any more correct.

I don't know, they definitely penetrated the truck frame just fine! But that's part of the problem with welding to a frame, especially one as thin as what's used on a one ton. It looks like the weld held the channel to the truck frame so well it actually ripped a piece of truck frame out when the body went for its' forward ride.

Yes! And besides just broken welds, the welds serve to act as a 'perforation' on the frame surface. The weld bead weakens the metal around it. If there's strain in that area, the perforating effect of the weld will make the frame break along-side of the weld.

The way roadhermit58 describes the mounting method is really the only correct way to do it. Member ghenges also describes a great way to mount a body as well, altho if you're going to mount a gooseneck ball or 5th wheel directly to the bed and not the truck frame, I don't know how well that would work out in that particular situation.

 

I took 20" out of my frame under cab, now a short box.
Welded back together, had no problems.

 

Just started reading your saga. The truck looks pretty good in the pics. If you shortened the frame just be sure to support the new seam well. Did you Z cut the frame or butt it with a fish plate? Also, be carefull what grade of welding rod you use on any future frame work. Off the shelf hardware store welding rods are usually quite soft (6013 etc). Make friends with a heavy equipment mechanic and he may be able to set you up with the best options depending on the frame material. Anyways, kudos to you for resurecting your truck. By tearing it all down you can eliminate any rust that may have been starting and it will probably last a long time. Be sure to check your back window opening to make sure it is flat and not going to twist the glass once installed.
Hope your buddy is helping out.

 

Yes, that's a little different than tacking something ONTO the side of a frame. If done correctly, a frame splice is often stronger than the original. Welding does funny things to metal. That's why it's so important to know what you're doing when you weld, not just getting 'good penetration', or a weld that looks 'clean'. I don't mean to be condescending so please don't anyone take my comments that way, but it's a real good thing to have at least a vague idea of what transpires when you stick two hunks of metal together and what takes place within the properties of the metal itself. Even the grinding marks left by the grinding wheel have an effect on what does, or at least COULD happen when a load is applied to the welded area. It ain't rocket science but it ain't a crap shoot either!