Boxing Frame

[topper]

I would like to make a front bumper for my 1976 K20 Suburban , but it would be heavier than the original plus a winch someday as well as recovery hooks . It seems to me that the frame at least at the front should be boxed or strengthened somehow . Have any of you done this or does it even need it ?

 

[Scruffy49]

If you look closely, rather than boxing in, factory frame doubler lower section… Granted, this is where the factory boxed section goes to open rail on a gmt400 K3500 c&c… But (elephant sized but) no different than a lowrider on hydraulics running a “wrapped” frame. Unless you fully box, the standard sections become weak points where the frame twists even worse than it did stock. And boxed frames rot from the inside out, as evidenced by a 92 K1500 Z71 turned parts roach I have out back…

 

[nvrenuf]

Tons of trucks out there with heavy winch bumper set ups (I’m talking about reasonable stuff), this doesn’t require frame boxing or strengthening.

That said, the general train of thought is that if you’re going to box the frame you need to box the entire frame.

 

[1lejohn]

You could add plates to the frame. I've seen a couple of guys do it for putting in a modern diesel engine. I's a similar approach that the steering box frame repair plate does. You could also add a cross member at the front of the frame horns. I think the heavy bumper might make the frame stronger by tying the frames together in the front. Like posted above you might just make the rest of the frame weaker.

 

[krusher74]

The frame at the back is the same thickness and is unboxed and would have had a trailer hitch rear bumper attached to standard bumper location to pull a trailer, the front should be fine for a winch.

 

[Rickf]

A boxed frame does an excellent job of trapping sand and road salt.

 

[Smtty58]

A boxed frame does an excellent job of trapping sand and road salt.

As the previous owner of 2 AMC era Jeeps with boxed frames, I hate them. Boxed frames and Rust Belt do not play well together. As an aside, I don't see how boxing the front section adds any strength. If anything, all the stress is on the bolts, in shear. If anything, just add a plate where the bolts are, but this adds the risk of rust jacking.