1985 GMC Sierra Bed Problem?

[ESP-Explorer-MX220]

I have a 1985 GMC Sierra that is in fairly nice condition, but the bed on the truck is in poor condition stability wise. My problem is that the bed is good but it seems that the bed supports are bad or something similar to that. Instead of the bed being level across the width of the bed, only the center of the bed where it sits on the chassis is level and the rest (fenders) seem to sag. I need to know how what the problem is and how to fix it (if it is fixable). If you can provide any pictures that would help a lot thanks.
Thanks for the answer but that doesn't quite answer my question. To clarify my question I need to know what the problem is and what to replace. Angain thanks for the answer not saying it was bad.

 

[roughboy68oh]

If you mean that the wheel well inside the bed seem to be sagging, they probably are. They just bolt in on those trucks and it's common for them to rust at the bottom and around the bolt holes allowing them to drop down. Unfortunately, when this happens, the lip on the bed floor is usually shot too meaning a new floor or a nice set of tubs slightly bigger than the originals so that they fasten to the top of the floor instead of the sides. It's not that difficult of a job really. Also, the channels that support the bed from side to side could be rusted. It's a common problem on that style of GM trucks just like rusty cab mounts. They're just stamped sheet metal that's spot welded under the floor and the bolts that mount the bed to the frame run through them. Replacements are available from many sources or you can make your own. There are 4 of them.