Fleetside Bed Sill Repair Suggestions

[adis]

I bought a decent '84 8' fleet bed locally to go on my '76 K20. The idea is to get it all put together as a work truck, so I'm not concerned about looks, only that it can handle a load and won't rust (much). I am a novice welder, and looking to use this as a way to practice, so forgive me if it seems ignorant. Everything on the bed is pretty good except that several (most) of the bed cross sills are rusted where the bed bolts go through.



I don't have the money to buy a whole new bed and I haven't seen anyone who makes replacement sills for the fleet. Do any of the aftermarket firms make a replacement bed cross sill for the fleet? If not, how is this type of repair usually accomplished? I was thinking of sectioning in pieces of sill from the old bed, or perhaps using 14 ga. 3"x1.5" steel pipe like this:



What I'm concerned about is the strength of this type of patch. If I section the piece by butt welding the ends to the old sill and spot weld it to the bed, will that be strong enough to hold a load at the seam? Will a repair like that hold with 1.5 tons in the bed? If I reinforce the butt welds will that do, or should I not section pieces and instead replace the entire length of the sill (which means grinding out a lot of spot welds...)

BTW, I'll be doing the repair with my Millermatic 140 mig using solid wire and gas, so I Should be able to get decent welds through the original sills which were 16 ga. Thanks for any suggestions or advice. - mark

[adis]

It's been a while, but I'm slowly getting this bed repair done. Picture below is of a section that I put in to replace a rusted part of the original sill, where the carriage bolt comes through. I used a decent piece from the original bed for the repair. I still wonder if simply butt welding the section in will be strong enough. Can anybody provide an informed opinion as to how I should finish this type of repair? Should I reinforce somehow (how?), or will it be strong enough as is? Thanks for any help. - mark

[cadillac_al]

I have contemplated that repair in the past and I always assumed my local sheet metal shop could make me some of those support ribs for a reasonable cost. I think your butt welding will be strong enough. There will be no pressure pulling them apart, only downward pressure forcing them together.

There is another post here of some good beds in PA. I would drive from MD to PA for a good bed. You may even find some closer to you.

[adis]

Thanks for the reply, Al. i'm already into this bed for probably close to $500, so i'm gonna see it through. Besides, i'm learning a lot in the process. i called around to some local fabricators, but just got, "our guy will get back to you," or no response. like i said this is gonna be a work truck, so i need it to be solid. thanks again

[old Rusty C10]

Id have cut he repair section larger and tucked it inside the existing section an inch or so in addition. you reair looks very good tho

[adis]

thanks, Bob. ive got three more sections to replace, so I'll try your suggestion. I'm just not sure that I'll be able to tuck it neatly in.

[lilspike]

I think I would have put some small pieces on the inside of the tube and plug welded them from the outside. Probably over kill or you could grind the weld flat and weld some patch over the weld seam like when doing a frame. Should be fine the way you have done it.
Matthew

[adis]

Matthew, I was thinking the same thing. But that's when it occurred to me to ask somebody if it was really necessary. I appreciate (and partially subscribe to) the idea that if over engineering it won't hurt the project and it gives you a comfortable margin of error, then why not do it. On the other hand, there is the question of value - is it worth it to spend what (for me) would be a significant increase in time spent on this part of the project, to do something that, according to the job requirements, doesn't really need to be done. I guess it's these kinds of cost-benefit analyses that get the experienced engineers the big bucks. All three of the replies to my post have said they feel the butt-weld is sufficient, unless somebody has a compelling contrary argument - i'm gonna drive on. Thanks everybody for your input.

[adis]

ok, so i've got the bed floor finished and back on the frame, and the wheel wells are all nicely undercoated, and ready to put back onto the floor. once i get to patching the bed side rust spots and adding the gas fill door to the pass side ill put the rest of the bed back together. ive got a few questions for anybody who might know:

1. how do i go about sealing the bed seams? is there some sort of flexible product that I put in between the seams during reinstall (kinds like gasket sealer), or is the sealer applied to the outside of the seam once the individual pieces of the bed are already screwed back into place? Recommendations on products (Fusor, 3M, etc.)

2. as far as the wheel wells go, is there a difference between left and right - they seem the same to me?

3. does anybody know what these pieces are and where they go? I forget.



Finally, an observation: this might be common knowledge, but apparently there were different ways to bolt certain beds to certain frames. my replacement '84 bed (i don't know if it was 2wd or 4wd) used bolts that go through the first and third floor sills in the front, while my '76 frame has holes for the first and second sills. luckily i noticed this as i was patching the sills, and took care of it by welding in bolt supports inside the second sill and cutting out new square holes in the bed floor for the carriage bolt. On my 76 K20 frame, the third bed floor sill sits above where the cross member is and to use the holes in it to bolt the bed to the frame, i would have had to drill a hole in the frame and the cross member, which I didnt want to do.

anyway, thanks for any info - mark

[hatzie]

Paintable flexible seam sealers. Here are a couple sources.
http://www.eastwood.com/autobody/sea...FdgPgQody60Amw

http://3mcollision.com/products/sealants

[pontgta]

Those pieces go on the rear of the bed sides.

[adis]

thanks, guys!