Frame twist?

[327power]

Hi, I have a 81' C10 stepside that looks like it is sagging when looked at from behind.
I noticed a lot of trucks look like that too. WHAT IS CAUSING THAT?
Is it the springs or is the frame slightly twisted? I hope its not the frame or I might just junk the truck and find another project.
Thanks!

[07montecarlo]

what kinda shape are your cab bushings in???

[VileZambonie]

Get out a tape measure. Typically it's worn out cab mounts and fatigued leaf springs.

[gold84gmc]

my truck is like that too...but the cab mounts are fine and it looks like just the bed thats twisted

[VileZambonie]

Measure from the top of the spring pack to the frame on each side and compare measurements

[gold84gmc]

is that where the axle mounts to the leaf springs?

[1980c10]

I had some of that with my fleetside, they said they could fix it, but that it may return to how it is now. they recommended shimming it straight. my truck had never been in an accident and has all of it's originial paint with no dents or scratches. I shimmed the bed between the bed and frame it looks great now and didn't take nearly as many shims as i would have guessed a 1/4- 3/8 an inch here and there make a big difference. check all body mounts and make sure they are the same thickness. then set your tires at the same psi, make sure you are parked on a level surface. then measure your frame make sure your frame sits level side to side then measure side to side and shim the body as needed. also make sure to check to seeif the rails under your bed haven't rusted (easy to see what i mean when you look under the bed). good luck.

[Irish_Alley]

some one could of pulled a "General Lee" and got some air.that will do it

[gold84gmc]

some one could of pulled a "General Lee" and got some air.that will do it

lol thatd be funny 

[327power]

Hey thanks everybody!
Yeah, I remember measuring the distance between the top center of the leaf springs and the frame. It's like 1" lower on the driver's side and annoys me. So it might just be the springs you think? I hope so. The truck is in really good shape being an 81' and everything. The only problems are a crappy repaint, the saggin' issue, and the weakess of a 250 I-6 (integral intake).
 

[VileZambonie]

It's almost always the rear springs. They're nearly 30 years old anyway. You can jack up the frame til it gets to where your measurement is equal and see if it looks right.

[327power]

I appreciate all the help!,
I really think that its the springs now. Mainly the leafs on the driver's side. I guess when I get back (deployed) I need to go out and buy some new springs for the rear all together. I might as well get new coils too. Awesome!
The truck is great, but looks crappy leaning on one side. Especially the driver's side so when you sit in the truck it sags even lower.
Thanks!

[SUX2BU99]

Great info in this thread. Pass side of my bed sags noticeably too. At the front of the box, it's 1/4" lower and might be lower at the rear of the box. Leaf springs are probably the culprit but now I know where and what to measure. Might just take the easy route for now and shim the bed bolts.

[327power]

Hey, its been a while, but I'm glad this subject brought so many great solutions to the problem of the dreaded frame twist.
It seems to be an issue on a lot of older trucks from all makes.