I'm new to this forum. I just bought a 2003 F350 SD Diesel and now am finding out that the rails (for lack of a better term) under the bed and hold the bed to the frame are rusted thru. The bed is in great shape top and bottom, just the rails are rusted out.
I am thinking about removing the bed, I understand that isn't too difficult to do, and welding or bolting in new rails. My questions are can this be done? Has anyone ever done this? Any explanation as to why the rails are rusting but the bed isn't?
Any help would be appreciated.

 

I replaced most of the rails on my truck. There probably is an easier way to remove whats left of the rusted rails than how i ground alot of welds and chiseled them off. Only explanation I have is the rails can hold moisture inside them.

 

Thanks for the response. Were you able to buy the rails at your ford dealer? Do you recall the cost?

 

I didn't even look at my local dealer. I went to a steel shop and bought square tubing. I think that cost me around $50.

 

Thanks, that's why I asked. I was thinking about doing the same.

 

Have to replace the rails on my dads 03' this spring. Luckily I have a fork lift so lifting the bed off will be easy. I plan on getting a spot weld cutting bit to remove the old spot weld. I'll get the new rails bent up out of some 304 stainless sheet and spot weld them bad on. Hopefully I can get in there to replace the fuel pump without dropping th etank.(while in rome, replace the fuel pump.

FYI the bed bolts can be a real bitch on some trucks to get out. Soak the captive nuts from underneath good before trying to remove them. I had to cut 2 of the bed bolts off my 04'. The Torx bits just shatter.

 

I haven't had to replace mine, but I have read up on it. I don't know about getting the supports from Ford, but a seller on Ebay has then for a high price. It appears that replacing them with tubing is the least expensive route, without compromising strength.
Mine show some surface corrosion, so I have soaked them with Fluid Film. I am keeping an eye on them, but I don't believe that I will have a problem.