I am trying to level my cab and it’s been kicking my butt. Everything looks good until I install the the rear mounts(shackles).

I have installed the front mounts and they are slightly thicker than spec but I figure the new rubber spacer will give and get there eventually. The rear cab shackles on the other hand are not working out. I am using the original mounts and they are in good shape with new bushings.

Prior to installing the shackles I had wood between the rear support and frame and the back panel looked nice and even from behind the cab. After installing the rear shackles the passenger side sits about a 1/4 inch higher than the drivers side . I removed all shims between the shackle and floor on the drivers side and it was still uneven. I even moved them all to the drivers side which is about 1/4 inch thick of shims and it was much closer but the cab was now off center.
I released the upper fasteners that go from the shackle to the floor, lifted the cab, re-centered it and installed the blocks again. The blocks give it the correct gap based on what’s in the factory manual. While lifting the cab I noticed that the driver side of the cab there is a lot of weight on the block where as the passenger side is relatively light and easier to lift.

I then tried to line up the holes between the shackle and floor and noticed the driver’s side shackle holes were slightly out board of the cab holes. So if the cab was raised more they should line up. On the passenger side the shackle holes are about 3/8” out board of the cab holes and in order to line them up the cab must be significantly raised on this side which in turn also seems to push the cab over to the driver’s side.
I did look closely at both shackles and they are identical except of course one is left and the other right.



Sorry for the lengthy explanation I tried to get out all the details but if anyone can tell me how to resolve this it would be greatly appreciated. I was thinking perhaps my cab is slightly twisted but nothin appears to be out of place.

Thank you!

1950 Chevrolet 1/2-Ton 3100