Is my frame bent??

[j_cst_10]

So my bed sits funny on my 1970 CST/10. I attributed it to the bed being 40 years old and such but I got to thinking and decided to do an experiment with frame straightness.

I leveled the frame right behind the cab with jack stands and took 2 points on each side of the frame to the floor where I suspected some funny business. Here's what I got.

DR. PS.

Point 1 23 3/4" 24"

Point 2 23 5/16" 23 1/4"

Brake drum to Frame 8 7/8 8 1/2

Is this thing tweaked or is this normal variance for a 40 yr old vehicle?

[j_cst_10]

Sorry the spacing didn't come out, the numbers might need some deciphering.

[mr48chev]

The difference in the drums to frame are probably due to the panhard bar on the coil spring rear end. as the truck goes up or down due to weight loads the rear end will move side to side a bit. To accurately check the frame you would have to have the truck put on a frame machine and have it measured.
Measure from the top of the axle to the bottom of the frame rail on each side and see if there is a noticable difference there then measure the wheel wells to the ground on each side and see if that difference coencides with the axle to frame measurement. What you be doing there is figuring out exactly where things aren't lining up right.
First check tire pressure then on a flat level floor do your measurements and do measurements in other spots to see if the frame is level and then if the box is level with the frame.
You may have worn out spring or you might have bad bed mounts letting one side sag. Or the frame could be bent a bit.

Photos of what you are looking at static might help a bit too.

[j_cst_10]

I leveled the frame on jackstands with the front 2 wheels on the ground and the back 2 off of the ground. Then I took measurements from behind the cab to the ground. The jackstands put that part of the frame level and everything else is based on differences between the level plane the jackstands create and the actual measurements.

The suspension does visibly lean to the driver's side but my method of taking measurements should cancel that out.

[mr48chev]

Unless you set the front end on stands under the frame there is a chance that the front suspension may be throwing you off.
about 35 years ago a part of my job was getting new cars to sit level for picky new owners who had bought the cars from the dealership I worked for. I often had to adjust for less than a half inch difference in static heiight from side to side or corner to corner.

Usually the truck or car sagging on the drivers side is due to having a vehicle that spent years going down the road with either a lone driver with no passenger or a quite heavy driver.

I had a patrolman tell me that my 48 was sagging on the drivers side one time. My answer was "fat driver" meaning me. He didn't see the humor in the answer but I weighed 280 at the time and usually drove alone.

What I am saying here is that if you put the truck with stands where you have them and right behind the front bumper and they are pretty level you first should be able to see if the frame is tweaked by checking to see of the rear frame horns are level. If there is a twist in the frame it will show up there and probably be quite obvious. If that checks out ok or really close. see if the cab and bed are in alignment with each other then see which one is actually off.
Problems could be bad cab or bed mounts or rusted out mounts or damaged mounts.

Remember that some of these trucks are almost 42 years old and a lot of them had a hard life in past lives. Heavy loads and driving over rough roads and fields. A lot of them carried campers that may have been too heavy for the trucks and often went in places that would cause some frame and body flexing.

[j_cst_10]

The more I think about this, I am leaning towards bad cab mounts and/or bed mounts throwing the alignment off. I figured the suspension sag was from what you describing.