Frame boxing/strengthening

[Levis]

We are currently in the process of reassembling my '72(361FT/ranger overdrive/t-18/np205)
Eventually, the truck will be fitted with a D60HPF

This will (hopefully) be used for hauling and gooseneck work. My big question is where are the weak spots in the frame, and what should be boxed/braced/gusseted in order to reliably handle loads in excess of 20k? The boxing of the entire frame seems like a lot of work. I am mostly interested in quelling any future problems with some light fabrication

[averagef250]

This is an F-250 4x4?

If it is you don't need to box anything. The F-250 4x4 frames are the same dimensions as the F-350 2wd frames. I've towed and hauled quite a bit with my F-250 4x4's. Sat over 30K GCVW a few times. Put your money into darn good brakes, step up to hydroboost for sure. IMO, the 70's and newer 1 ton rear drum brakes work better going down a heavy grade with weight than rear discs ever dreamed of. Rear discs grab then incinerate. Drums fade slow and still work when they're glowing.

[Levis]

whoops, sorry, This is a twd f-250. I know that the 4x4 frames are built stronger.

Average; I have read many of your posts and must say that I cant believe what you have done with them pickups. I saw the picture of your flatbed with the 4bt. Awesome truck, Man!! Mine has a long way to go, but I refuse to give up, so it will get done. It's amazing what you can do with what so many other people view as an "old truck". Anyone can take out a loan to buy a spankin new truck, but they're a hundred thousand of them exactly like it already on the road. That don't make it so cool, now does it?

[averagef250]

Thanks for the compliment! I've had some newer 90's trucks too, they seam to wear out faster and I'm just never inspired to keep fixing them like I am with the old ones.

The 2wd F-100 and 250 frames are much different. While I haven't seen a bumpside F-250 2wd frame fail I have seen several dentside ones give out. Every one was in the driver's side frame rail, one between the cab and bed and the other two were both at the steering box where the engine crossmember is welded/riveted to the frame. The cracks both went right through the rivet hole in the lower lip of the frame where the aft flange of the engine crossmember connects. All three were 460 trucks.

[Levis]

Thanks Average! it seems as though it would be simple to strengthen now, rather than waiting for it to crack and then fix.

One more question; Most all of the crossmembers and components are bolted/riveted to the upper and lower frame lip, not actually to the face of the frame, so when I built the trans crossmember, that is how I did it also. Why do so few components get attached to the vertical rail?

[averagef250]

The surface of the web of a steel beam is the majority of it's strength. an interuption in the surface of a steel part is a stress point. The 4x4 frames are boxed in the front with the engine crossmember welded to the inner boxing and only a small 3/4" or so weld to the outer frame surface.

[warponyxlt]

i think that in front of the front crossmember would be a good place to look for cracks to they cracked there on my 72 but i think that was from a wreck long ago just my

[averagef250]

On a 2wd there is zero stress on the frame rail forward of the engine crossmember, that part of the frame isn't even a structural part of the truck. All it does is support the core support and front bumper. If yours cracked it was from a wreck.