Rust! Cross Sill Replacement

[bowmank10]

Started to work on my shortbed box today. I ordered 2 new bedsides and a front bed panel but planning on repairing the floor. I've searched up and down and can't find a company that makes replacement shortbed fleetside cross sills! Thinking about making my own out of sheet metal if I cant find any repro ones. Anybody have any ideas?
Here's a pic of both cross sills that need replacement,

[Vengfulcujo]

I was just gonna ask the same question.  I think I'm going to end up making some out of channel.

[jaredts]

I used square tubing to replace mine.  Worked just fine.

[bowmank10]

Do you know what the dimensions were on that tubing?

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[Don5]

Ok guys I have the same problem as the rest of you. I happened onto a guy that had some parts for sale. He showed me a piece of a cross sill that he had made for him. I got the phone out and took pics with a tape measure showing the dimensions. Now these measurements are for the 81-87 body style. I have a 79 but I have not checked the dimensions yet.

Here you go. The cross sill is u shaped and has a flange at the top of the u. From the flange to the bottom of the u is 3 inches. The bottom of the u is 1 5/8 inch wide. The flange is 1/2 inch wide. I think he had these cross sills made in 8 foot lengths and he cut them to length as he needed. They were made out of 10 gauge metal as well. They looked identical to the ones that come from the factory. He had a local sheet metal company bend them up for him. I would look in the yellow pages and see if you have a sheet metal company or maybe go to your local heating/cooling company that has a long metal brake. I am sure some body should be able to make them. I hope this helps. 

[jaredts]

Pretty sure my tubing was 3" square, 11 gage.  The originals are more like 18 gage, but thicker shouldn't hurt.  It would be pretty easy to form up factory style replacements on a brake.  I should do some at work and sell them--left the forge shop some time ago and now work in fab and machine.  We have a laser and cnc brakes.

[Don5]

I thought he said 10 gage but I am probably mistaken. It was pretty thick and very sturdy. Like I said it looked just like an original piece too.

[jaredts]

His replacements might have been 10 gage.  At .135" thick, that's a stout replacement--nothing wrong with that.

[bowmank10]

What is the best way to remove the old rusted cross sills? I'm planning to trying to drill the old spot welds and air hammer them off

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[jaredts]

Find all of the spot welds and drill them out.  Not much fun but the only real option.

[87max]

AMD makes complete floors, years ago (20) I replaced just the sills. I wasn't wasting my time this time just got the entire floor.

[Captkaos]

This site sells the whole bed floor also, but it has to be shipped truck freight.