Got my bed in, but something isn't right...(long post w/pics)

[mweishaa]

So when I had my truck at the painters, there was some mis-communication and the cross sills got tossed with some of the other rusty bed parts. I got some fleetside cross sills from 66-PMD-GMC. Thanks man, and good meeting you! So I cut them down, painted them, and got them installed. I had to drill the end holes, the rest lined up.





OK, only a couple of my drilled holes weren't exact... but a quick trip with the angle grinder and they were fully adjustable.


So I was doing all of this with the bed on the truck. I really don't recommend this. And I also don't recommend doing it alone like I did. That last strip in the middle was the toughest, shimmying boards and whatnot to close the gap. But I finally got it. The wood, strips, and bolt kit are from Mar-K. Pine boards, sealed and painted gray.


OK, so now to my problems.
1. you can kind of see it in the pic above, but there were 3 holes in the angle strips (original, not replaced) that I don't have bolts for. I drilled those holes through the wood, but I am not sure what they're for. I emailed Mar-K to see if I got shorted some bolts/nuts.

2. I also got the rubber mounting pads. For a longbed stepside, there are 10 pads. If you notice, I only have 8 bolts. What are the other 2 for?

3. Now the big problem. My bed is only supported at the front and rear. The other 4 mounting points have a big gap. I put the pads in there, but as you can see it's not even close.

Green is the rear one, then look at the one in red


Here is the front. Note the green and red... and what is the one in the middle? There is no bolt for this one, but it seems like there should be.


Welding isn't a problem, so I could fab up some supports to put in there. I'm just kind of confused about it. Why the 10 mounting pads, but only 8 bolts? Do I just fab up supports, even for that one without a bolt through the wood, and secure it there? Need some guru help on this one.

[Alan's Classic]

The rear sill on yours is different than on my 65. It's like an inch taller.

[Alan's Classic]

I'm thinking the rails that were replaced are the wrong year if your rear sill is the original. What year is your truck?

[mweishaa]

Oops, thought I put that in the post.. sorry. 1964 GMC, longbed stepside.
I think they are original. I didn't replace them, and everything else seemed to be original when I got it. It's a 3/4 ton, if that matters.

Now that I think about it, the two shorter sills in the middle, that just attach to the wood, are almost touching the frame. So I couldn't drop it.
The cross sills I got were from a fleetside, so I'm wondering if the original ones had an exra spacer on them, like that one in the front.

[Alan's Classic]

I can't give specifics cause I don't know, but I think the 3/4 ton will matter in this case. Someone else with a better clue will chime in soon.

[luvbowties]

Hello, mweishaa,too bad painter tossed original sills! These bolt-in kits tend toward a jig-saw puzzle when spacing, interchanging boards, strips etc. to adequately cover all the bedspace! I've got a couple of ideas where probs might have come from. 1st, is yours a 3/4 ton which maybe has different hole-design or # bolts going all way thru wood? Maybe it uses a rubber pad(between middle sills and u-shaped supports) with only short bolts up thru support, pad, and then the sill-flat, with a nut on top of the sill-flat? 2nd, there maybe more differences between fleet-and step-side sills than we detected? 3rd, maybe a difference between gmc vs. chevy; i.e., like in some even-same-year-apps, gmc only offered leaf springs where chev had coils.
Idea: since u already drilled holes from the top & down thru the wood, who'd ever know if you epoxied or butyl-rubbered some cutoff bolts into those holes--only the pretty bolt-heads would show?!?
Hope this is not too much "rigging" to suit you. Luck with your project.
sam

*Sorry: somehow I got the idea you bought gmc sills to go on a chevy; still, the ones u got may be from a chevy, like too close to detect a difference.

[mweishaa]

Originally Posted by luvbowties

Hello, mweishaa,too bad painter tossed original sills! These bolt-in kits tend toward a jig-saw puzzle when spacing, interchanging boards, strips etc. to adequately cover all the bedspace! I've got a couple of ideas where probs might have come from. 1st, is yours a 3/4 ton which maybe has different hole-design or # bolts going all way thru wood? Maybe it uses a rubber pad(between middle sills and u-shaped supports) with only short bolts up thru support, pad, and then the sill-flat, with a nut on top of the sill-flat? 2nd, there maybe more differences between fleet-and step-side sills than we detected? 3rd, maybe a difference between gmc vs. chevy; i.e., like in some even-same-year-apps, gmc only offered leaf springs where chev had coils.
Idea: since u already drilled holes from the top & down thru the wood, who'd ever know if you epoxied or butyl-rubbered some cutoff bolts into those holes--only the pretty bolt-heads would show?!?
Hope this is not too much "rigging" to suit you. Luck with your project.
sam

*Sorry: somehow I got the idea you bought gmc sills to go on a chevy; still, the ones u got may be from a chevy, like too close to detect a difference.

I had some of the same ideas about hole patterns. But.. the wood I got from Mar-K had the holes pre-drilled. And there are 8 holes, which match the 8 bolts they sent me too. So for the bed-to-frame stuff, it seems like they would know what they're doing. As for the seemingly 3 extra angle holes per side, I'm a little stumped. If I can get the same bolts, I could just put nuts on them underneath and call it a day - they just won't really do much functionally. And I can fab up sometime to fill the gaps between suports and frame. I would like to know the whole story though.

[63 Spud]

The sills are different between a step side and a fleet. I took a picture of my step side with no bed wood and there appears to be a piece of metal spot welded to the sill to fill the space you have on yours. I don't think there is a difference between 1/2 or 3/4 ton.

[mweishaa]

Originally Posted by 63 Spud

The sills are different between a step side and a fleet. I took a picture of my step side with no bed wood and there appears to be a piece of metal spot welded to the sill to fill the space you have on yours. I don't think there is a difference between 1/2 or 3/4 ton.

Thanks! That answers that question. And this is what I was suspecting since you can see one of those in my pic... the one in the front has that.

Still not sure why I have 10 pads though. Having slept on it, I think I can use those by bidging the gap where I don't have a bolt going through the wood, and just bolting that together underneath and use the pads there.

[mweishaa]

Went out and took some measurements of the gaps... well what do you know... same size as the shorter bed strips that just attach to the wood. Good thing I had longer ones that I cut off. But the two rearmost gaps were a little shorter. So I took a scrap from a bigger cross sill, cut it and bent it to the right size. You can see them on the left, one is done the other is pre-bending.


Here they are installed. I didn't tack weld them to the sills, because a) they're painted and I didn't feel like it and b) I don't think they'll move all that much. I can check them, and if they end up shifting I can do it then.
It's not like I'm doing the Baja rally or anything. For the one without the wood bolts I just put in a shorter one and bolted it together. And I got to use my extra two rubber pads this way.