Help please. Bed alignment issue.

[SunSoaked]

Replaced the cab and core support bushings today. The body lines still don't line up like I want. There's not much side to side adjustment in the cab mounts. Is there any lateral adjustment on the bed to frame bolts? I have a suspesion my frame may be tweaked a bit.

[Matt Man]

How off is it? When I did the cab mount bushings my passenger side was lower by a bit and had to shim it up to get it level. There was already a shim on my back passenger side cab mount. When I got it aligned, they also got the thrust angle correct and they made sure my frame was not bent to begin with and it was fine. The alignment and body shop told me the older trucks require more shims and adjustments to make them "square" per say.

[mongocanfly]

Any pics?....so we can see what your seeing...

[SunSoaked]

I'll get some pics this morning. There seems there may be two issues.
1. The horizontal belt line does not line up on the driver's side. The front of the bed is about 1/2 higher than the cab. If I jack the back of the cab up until it lines up, then it peaks in the middle and looks like the bed tilts down towards the rear. It looks like the front of the bed sits too high but, I believe it sits directly on the frame?

2. Looking down the side, the front of the bed is about 1/2 inch off from the sides of the cab. This creates a gap between the cab/bed to be different from side to side. From above, it seems I need to rotate the bed clockwise a degree or two.
I hope this makes sense. Lol

[old Rusty C10]

the bed should sit square on the frame. I just had this problem with my C20 that was hit on the side. I ended up finding out the bolts in the rear cab mounts were bent. I used new bolts and some shims and she sits fine now

[mongocanfly]

Sounds like you may need to shim the cab up higher to match the bed line......body shimming is just part of it so dont hesitate to do it...your new cab mounts may not be the same as factory..
Loosen the bed mount t bolts and see if the bed has any side2side movement....also the cab could be off side2side a little...

[Dead Parrot]

There is some side to side and front to back adjustment on the bed bolts. At least there was on my 75 C10.

My bed sat directly on the frame but no telling what a PO might have done on yours.

[SunSoaked]

Thanks DP.
I removed and replaced the passenger fender today. I realized the cab was all jacked up in the mounts. I left the bottom of the cab and core support mounts off so everything is just floating at the moment. I want to loosen the bed mounting bolts and try to get everything lined up horizontally first and then add shins if/where needed.
Question: Are the OE bed mounting bolts carriage style heads? The PO had the bed LineX'd and I can't easily see any head bolts. Someone mentioned T-Nuts and that threw me off.
And...are the nuts accessable without removing to he saddle tanks?

[dmack91]

Carriage bolts were used for the bed. They often spin in the square holes, so don't be surprised if you have to cut them out, or weld nuts to the top.

And yes you can get to all of the nuts without removing the tanks. Eight for a long bed, six for a short bed.

[SunSoaked]

Thank you dmack.

[old Rusty C10]

and if you need replacements you can get galvanized ones in Home Depot as opposed to spending the money at LMC its what I used

[Dead Parrot]

Spray your bed nuts with with penetrating oil several times before attempting to loosen the bed bolts. Giving the oil a couple days to work can really help.

If your spare tire is under the bed, it has to be dropped first.

Something heavy to hold the new bolt in place really helps if it is a one person repair.

[SunSoaked]

Thanks. I located the 8 bolts last night. Fortunately, the PO did a frame off resto before losing interest and throwing it all back together to get rid of it. One of the reasons I bought the truck was because it was a 100% rust free Arizona vehicle with a freshly sandblasted and painted frame and undercarriage.
Every nut and bolt on the chassis is brand new and shiney still.
I could see that the nuts and washers had room for back and forth adjustment because I could see space in the frame slots.
Tonight I am going to loosen the 8 nuts and then try to align the bed and cab and get it centered on the thrust line. Then, hopefully, I can shim things vertically.