Author Topic: 1976 Crewcab Shortbed, bed is too low!  (Read 232 times)

Offline RADustin

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1976 Crewcab Shortbed, bed is too low!
« on: April 02, 2018, 09:27:52 AM »
Greetings,

I dropped the body on my project '76 this past week/weekend and the bed is too low as compared to the cab. It's about 1/2" too low on passenger side and 5/8" too low on drivers.

Some specs of my build:
-1976 Crewcab Cab
-1977 CCLB frame, cut to shortbed
-I assume late 70s bed floor, aftermarket bedsides
-  PN 30-1161 Body Mount kit (73-80 crewcab), tightened up till the pieces bottom out. Further tightening won't suck the body down anymore.

The bed is sitting directly on the frame. I assume this is how it is supposed to go. Bed fits fine.

From my measurements so far the cab is level with frame, but I will continue to measure different ways to confirm or rebuke. All 6 of the cab mounts have pressure on them, so things 'look' correct. I have the square shims on the front two body mounts, 1 on each side. The 4 rear mounts are body on rubber, no shims.

The frame is straight. I measured it out well when I cut it to a shortbed. The bed to cab gap is uniform top to bottom.

Anyone have some ideas? I can understand the bed being high, and cab low- but not the bed being low. I really don't want a body lift, uneven at that to make things right. I'm hopeful there is a detail I am missing.

pics-




Thanks.

Online 1967KaiserM715

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Re: 1976 Crewcab Shortbed, bed is too low!
« Reply #1 on: April 02, 2018, 12:02:23 PM »
There are some thin rubber bushings that go between frame and bed, but they are only 1/4 inch thick.

Other then that, it's possible some work may be required to make everything line up. I'm assuming cab had no work done, and the bed was rust free too. And they are both GM factory parts.

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Offline RADustin

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Re: 1976 Crewcab Shortbed, bed is too low!
« Reply #2 on: April 02, 2018, 12:27:44 PM »
the cab is stock, rust free believe it or not.  super clean cab. 

The bed floor is stock, again rust free and in great condition.  The bedsides are aftermarket. 

I'll have to checkout these bushings for the bed, I haven't seen something before. 

I guess that's all I can do is to shim everything around?  It doesn't seem like anything is obviously wrong. 

Offline VileZambonie

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Re: 1976 Crewcab Shortbed, bed is too low!
« Reply #3 on: April 02, 2018, 01:16:54 PM »
Did you raise the bed floor? The only thing you can do is shim the bed to make it look right. The bed floor does sit directly on the frame but spacers will be needed to get it level at this point.
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Offline RADustin

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Re: 1976 Crewcab Shortbed, bed is too low!
« Reply #4 on: April 02, 2018, 01:36:50 PM »
no the bed is stock. 

I just don't understand why a stock bed, stock cab, stock frame, new cab bushings...etc and it's off this much. 

Doesn't really make sense. 

Offline VileZambonie

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Re: 1976 Crewcab Shortbed, bed is too low!
« Reply #5 on: April 02, 2018, 03:26:37 PM »
So where did you drop the body then? I'm not understanding how it's stock with a body drop?
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Offline RADustin

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Re: 1976 Crewcab Shortbed, bed is too low!
« Reply #6 on: April 02, 2018, 08:55:56 PM »
there is no body drop. 

It's actually a lifted truck. 

Offline winky

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Re: 1976 Crewcab Shortbed, bed is too low!
« Reply #7 on: April 03, 2018, 11:22:14 PM »
try measuring from the body mount to the fame rail and see if they are the same on both sides. are you 100% on your cab and frame years??

Offline VileZambonie

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Re: 1976 Crewcab Shortbed, bed is too low!
« Reply #8 on: April 04, 2018, 05:59:25 AM »
there is no body drop. 

It's actually a lifted truck.

Okay so I guess you confused me by saying
Quote
I dropped the body on my project '76 this past week/weekend and the bed is too low as compared to the cab. It's about 1/2" too low on passenger side and 5/8" too low on drivers.

You are saying you put the cab and the bed on and the result is misalignment..

The correct thing to do is install the cab onto the new mounts, washer, spacers and loosely fit the bolts. Even inflate the tires, make sure you have no suspension lean, jounce the suspension and then measure to ensure the cab is level. Make sure your doors are properly fit and operating flawlessly with good gaps. The doors should close with no issue and will be in line with the body line. You may need to add shims in some places to achieve the correct position height of the cab despite new body mounts. When I do this I will add 1/2" extra shims under the center mounts to allow me to initially set my fender alignment to the cab and to install the core support without resistance. Install and align front fenders to the cab and doors until you achieve the proper fitment and tighten all bolts. Place the front core support mounts into place and carefully install the core support. Now jack the cab and remove the extra shims you added and lower it onto the mounts with the correct spacers in place. Recheck fender alignment and height, add shims as needed. Check each mount location for gaps and add shim as necessary to avoid uneven tension on the body mounts which will lead to fender misalignment if you don't. Once you are satisfied, evenly tighten the body bolts starting in the middle, to the back and to the front. Recheck your measurements. At this point your cab should be nicely supported and positioned with no adverse effects on the body lines.

Take a look at all of the trucks out there with atrocious body lines, it is because cabs deteriorate, soften, shift, frames settle and twist, suspension wears out, the core support twists and settles etc. It's like banging on a piece of metal with a hammer when you drive these trucks for 20- 30 - 40 years. Plus many of these trucks rolled off the line with loose fitment issues.

So once the cab is properly set, position the bed and if you still have alignment issues, use shims between the frame and the bed to achieve the proper body lines.
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Online 1967KaiserM715

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Re: 1976 Crewcab Shortbed, bed is too low!
« Reply #9 on: April 04, 2018, 06:32:55 AM »


The bed floor is stock, again rust free and in great condition.  The bedsides are aftermarket.   

I bet the bedsides are off, I have aftermarket bedsides with an original floor and tailgate and there is some issue with alignment with the tailgate. I don't have it on the truck yet, needs a little work on one bedside.


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Current Vehicles:1985 GMC K10(Daily)
1975 Beetle(not running) 1985 Mercedes 300D(not running) 1952 M35    1967 M715(not running)
1991 GMC K2500(under repair)