I just bought a 1985 GMC Sieraa Clasic 3/4 ton longbed. It has a 4" lift on it with 35's, outside, inside, engine everyhitng is cherry. I will post pics as soon as I take some.

My question now is, how do I go about boxing in the frame? I have a pretty good idea but I wanted to make sure Im going to do it the correct way. I want to also box in by the steering box for more strength. Can any one give me a few pointers, any one have a ny pics??

Thanks You,
Lance

Why box it? Just reinforce the steering area (it's pretty much the only thing that ever gives trouble) with the weld in plate (called a repair plate but, you can be pro-active) and you might go ahead and add a brace.

Otherwise, let it flex. That's what it was designed to do and you are not likely to have problems with it fatiguing anywhere other than the steering box. The only way I would box it is if I was doing SERIOUS tractor pulls, airing it out repeatedly, etc. People go to great lengths to add 1-2" of flex to the suspension, why would you do so much work to remove flex without substantial benefits. It looks funky, seeing the frame twist but it really doesn't hurt. In fact, if you box the frame and don't do it right, you may cause more problems than you fix. Especially if you create/leave weak points where all the flex/stress gets concentrated.

Just my opinion but, I have no thoughts or desire what-so-ever about boxing my frame...

I see it everywere. A couple of my friends frames are cracked were the shock mounts are. I will go ahead and just weld in the brace for now like you were talking about. I plan on going to hydro assist steering and I wasnt sure if the frame would hold up. In the back I do need to box it in one 1 location on each side. I plan on running a piece of DOM across the fram like a cross member and mounting my shocks to that. Anyone else ever boxed in part of your frame? Any pics of steering braces made??

Thanks

Well, I'm running hydro-assist too. Actually, it takes the stress OFF the frame and makes it less likely to break the steering box loose. As for the shock mounts, that's also a given but everyone builds new mounts anyway once the get serious. Mine are mounted to a cross member made from a piece of 1.5x.250 square tube with 2"x.250 angle iron welded to the ends for mounting. It aint going anywhere. IMO, DOM is a complete waste of money for mounting shocks. Square tube or HREW will be more than enough. I would use DOM only where it is a matter of life/death, like cages, suspension links, etc.; or where weight must be kept to an absolute minimum for a known minimum acceptable strength.

And, as for boxing part of it, again, I warn you about creating stress focus points. If your planning on boxing where the shock cross member attaches, I just don’t think it’s necessary or a good idea. I ran a frame machine for years and I think that this will cause you problems. I've seen (and fixed) a number frames where someone scabbed in a piece of plate to spice in a frame horn, or shorten/lengthen a frame, etc. These were mostly logging and farm trucks with stretched frames and such. That “fish plated” area has about the same effect as boxing part of the frame. What you do when you add those scabs (or box a small area) is create an area which will not flex, welded into the frame that was built to flex. The result is that the frame flexes, as it was designed to do, and work hardens next to the rigid area. Before long, you have a fatigue crack. At least that is my theory. One thing I know for sure, I’ve seen frames break right beside the plates many times, and I've cut a bunch of junk like that out and fixed it right. I’ve never had them come back for a broken frame anywhere near the area I pieced in. It certainly can and has been done successfully, but you can’t do it add-hoc without thinking through the effects.

Any pics of steering braces made??

Thanks [/B]

www.offroaddesign.com has the brace...........pics of it installed on my site www.blazzinor.rockcrawler.com

Worth it to have both the brace and the weld in support kit.

Here's one pic of it installed.

i have done the weld in, and it really stiffened the steering! bolt-in is tomorrow nite

Alright, im convinced not to box in the frame. When Im welding in my cross memember for the shock mounts should I just weld it into the inside of the frame? Thanks

I bolted mine in using 3/8 grade 5 hardware with split ring lock rings and nylocks. :shrug: Weld in is fine, but I can easily relocate mine to tweak the shocks. I'm also planning to loose about 30" or more off the tail and move the axle 15-20" forward to reduce the wheel base. So, I will definitely be relocating the shock mount bar. Most people just bolt those things in, but you can certainly weld it if you prefer. Also, remember that the factor put everything together using relatively soft 3/8 rivets, and you rarely ever hear of a rivet coming loose. I've also relocated my rear spring hangers once already and I replaced all the rivets with these same bolts. Basically just replacing rivets 1-to-1 with the grade 5 bolts in the new location. I'm not a bit worried about them not holding, and that's on spring hangers...

How does your relocated rear shock conversion ride? How did you determine 50 degree angle for the shocks? How did you calculate shock length required? I'm planning on some similar mods for my Burb.:smokin:

Rides awesome, very similar to the stock setup, just a little better. I am using the Rancho 9012 shocks, about as long as you can get them. Angle was based on what many others before me have calculated based on articulation maximization. My buddy over on www.coloradok5.com makes and sells the relocation kits if you are interested. Good price, too. Depending on where in the country you are there are others that make them, or if you can fab they are pretty simple in reality. He's located in Eugene, Oregon. Shock length was then calculated knowing the full extension length of the 9012's and doing the math.

Let me know if I can help ya.