The Stovebolt Site Forums The Parking Lot Big Bolts keeping bed and frame together

So, I've just gotten my new 1950 4100 back from Mo. It has had a fair amount of restoration and a semi-custom aluminum bed. The bed is spaced out from the frame (to clear the wheels) with what appears to be scrap lumber pieces; and there are several apparently fabricated U-bolt like pieces holding the bed to the frame. This seems kind of skimpy to me. I really couldn't find a picture of how the stock (platform)bed is supposed to attach to the frame; and I don't know how folks typically attached aftermarket beds. Any information on this would be appreciated.

That's pretty much it. Usually some U-bolts or some type of threaded rod clamps are used. On a flat bed we put on one of my International trucks last summer, we laid down a piece of 1x4 board on the frame first, then clamped the bed down. The reason for the wood was, that there were some rivet heads on the topside of the frame rails, such that the steel channel would not fit flush to the frame. By using the 1x4's, we were able to drill holes where these rivets were, and provide a flat surface to clamp the bed to.
(Hope that made sense!!)

That's how mine is attached.

The factory approach to mounting a flat bed on one of these trucks is basically what you describe. Take a look at an assembly manual and it will show the wood and ubolts.

The wood "runners" also help prevent squeaks and wear as the bed and frame flex and twist. don't do it like my 62 is-the PO welded the back of my bed to the bumper and welded the bumper and the front of the bed to the frame.
Speed

OK that's interesting. I'll still probably have to replace the wood (looks old, doesn't seem to fit right). Does anyone know what the preferred material would be? Possibly pressure-treated lumber, to reduce rot? On the U-bolt like fasteners, what typical grade/size bolts are used?

You should probably use just normal white oak. pressure treated is pine and soft, and the oak will be more rot resistant it this case, how much does it rain under your bed?

Go to a big truck shop and have them make you some u-bolts similar to how they would make them for your rear axle, you probably won't find them in just the size you need any where else. the truck shop will have some advice also.

On the treated wood use..dont. Appox 2 yrs ago the goverment banned the CCA treated lumber we all used for yrs. In its place we now have ACQ treated lumber. This stuff is nasty, and will eat most metal that come in contact with it. Fastening it requires the used of coated or galvanized hardware. It will eat right though a common nail or bolt with a few years. Its causing a lot of trouble in the home building industy because of lack of knowlage by the contactors.
For use on trucks there are now some lumber coming out, using a differnt kind of treatment that doesnt require any special fastener, but its pricey. Another thing one might do for a bed is use cedar or one of the vinyl decking products on the market.
On the frames all our yard trucks use white oak. On trucks with tied down beds we use 5/8" U bolts, made from grade 8 rod stock. Double nuts are also a good idea.

I was thinking about using untreated lumber that was thoroughly dried and coating it with bedliner stuff like Line-X. Anybody tried that?

I just got my fresh off the press 1947-1954 Truck Facotry Assembly Manual. I was hoping there would be diagrams showing how various bodies are attached to the frames. BUT all the diagrams I see are without any bodies. Am I missing something, or do I need a different kine of assemby manual?

Most of the bodies, except for the pickup beds, were made by other aftermarket manufacturers, and therefore would not likely be shown in the Chevy manuals. But in most cases, the procedure would be as outlined above.

I know I've seen those pictures, and I thought it was in the Assembly Manual. I also have a GMC maintenance manual, I'm now wondering if I sent you in the wrong direction, and its actually the repair manual.

If I did, I apologize. But you'll be glad you have the assembly manual!

I AM happy I have the assemby manual. And I think I know how to proceed on the job. But those diagrams must exist someplace.

With an aluminum bed it sounds like your truck may be more of a custom than bone stock appearing. I don't know where to get them(and it probably won't be cheap), but I have seen some approx. 1X4 teflon strips used on some type of machinery that would likely still be there when the carcheologists dig up the remains of your truck thousands of years from now.

Take a look at this link http://www.gmupfitter.com/publicat/1999_BB/MDPDF/C.PDF
Page 50-53.

Gives the best info on mounting bodies. GMUpfitter.com is the best source of late model tech info on GM Medium Duty Trucks and, as a GM salesman, I use it almost every day.

Another type of insulator, or issolator material often used on heavy dump bodies is a rubber strip of about 5/16-3/8" x 3" of 90 durometer rubber. It's available from industrial supply houses. Old rubber belting could be used also for your project.