The Stovebolt Site Forums The Shop Area Paint and Body Shop Cab won’t sit level

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!

I would try blocking the cab level with the frame and centered, and then install the shackles, using all the slop in the holes to line them up. Maybe push the frame portion of the brackets up as necessary. Then tighten all the bolts. You could cheat a bit and put shims between the frame and shackles to move the rear of the cab to center it.

I haven't tackled that task yet, but can understand how it would be frustrating. Good Luck and let us know how it works out.

What condition are the front cab supports on both sides? Same for the floor boards!
If they are sound, I would suggest that you remove the rear shackles and place 3/4" boards between the rear cab and the frame near where the shackles belong. Then add shims on the front mount which is light in the loafers until the the two mounts have the same amount of cab weight on them. Tighten the front cab mount bolts.
Now install the rear shackles and remove the boards. The cab should now sit level. If not, then there is something wrong with one or the other of them or their mounting holes in the frame.

I was out taking measurements tonight of the floor pan shackle holes to floor pan edge, compared the left and right shackle dimensions and measured the distance from the frame to the holes and all looked spot on. The shackle holes in the frame on the side with the biggest gap are about 3/32" higher than the low side. That is a minor contributor in my eyes. Not aircraft tolerances but good for its time!

I attached a couple photos showing the gap difference with respect to a planed piece of wood that is about an inch high.

The picture with the piece of wood under the cab on the passenger side corresponds to the picture of the shackle with all the shims, lol. The ply wood in the gap is 3/4 and I probably added another 3/8 to get the holes to lineup in the cab. The picture with the piece of wood running up against the back of the cab is the driver side.

I will take another shot at it tomorrow night with your suggestions and let you know how I fair.

Thanks for the advice as always!

Maybe you need to move those frame holes that are high by slotting them.

Carl's suggestion is valid and probably an essential starting point.

Do you have the Shop Manual?

Brothers video.

A couple comments about the Brothers video.
It doesn't really help him do much more that restore the shackles. No tips on getting the cab level and centered.
Another thing is it shows greasing the rubber bushings with wheel bearing grease, which is petroleum based. Not good for rubber products. If you're going to grease them, use silicone grease, which doesn't deteriorate rubber products like petroleum based grease may do.

Your shackles and the mounting holes in the frame are fine. They are likely becoming out of wack because of the front mounts. When the front mounts are not right side to side, the shackles have no choice but to become wonky.
Re-read my early post and do what I recommended to find your problem.
Carl

Got it. Doesn't help him, wrong grease. Just trying to do my best for the post and the poster.

I totally understand. I thought the video was interesting and valuable.
I was definitely not trying to cast aspersions at you. Keep up the good work.

Carl,
I followed you advice and it did make a significant improvement. There is still a difference but only about an 1/8” in height and side to side! I can definitely live with that.
Klhansen, I still may consider slotting the holes on the one side to get that last 1/8” but it’s close enough for now and I’m sure in 1950 they wouldn’t think twice about it.

Thanks for the all the help, Carl, klhansen and Bartamos!

Had to jump in here because I'm I just finished replacing the driver's side outer front cab mount and part of that floor; not my first rodeo there and I expected to see a height difference but this thread sure helped me to understand HOW to get the cab level! That shackle setup (and adjustment) is a different setup than what I've worked with before. About to start on the passenger side, its much better but that outer mount is also failed (so the driver's side is understandably higher right now) - but knowing this I am able to do a way better job at making sure the cab is "sitting pretty" before I start burning the new metal in.

So Thanks!! [u][/u]