The Stovebolt Site Forums The Shop Area Paint and Body Shop Cab mounts

I am rebuilding the cab mounts on my 50 3100 and the rear mounts are shackle type. Does anyone know any torque values when tightening the nuts on the shackle? I am not seeing anything in the assembly manual telling how tight to tighten them. Lacking any other info I guess I will just throw thread lock on it and go moderately tight.

From the truck manual "tighten securely". Use shims to adjust height.

I know that they are pretty stiff to bend even after 60+ years they should be tight enough that with a load on them they barely move. I figure they have to have engineered them figuring 200lbs or more per corner and then bumpy roads making them move straight up and down since they are rigid on the front mounts. They were changed in late 1948/early 1949 because the center mount was causing stress cracks in the cab. Same reason for the change in radiator mounts from one center mount to two spaced a few inches apart.

I just installed a rebuilt set yesterday on my 3100. I tightened the side plates just until I knew the new rubber bushings were properly seated. I "securely" tightened the frame brackets as per manual. My suggestion if you've never reinstalled these before, is to loosen your front mounts and keep all the mounts loose until you have them lightly bolted in place. I also used a large dfift to help line up the frame bolt holes to the brackets. I plan on retightening all the bolts after some use and also check the clearance alighments then when they have settled out.

The side plates were my main question. I wasn't sure how much i should squish the rubber bushings on them but dont want them to come apart either. I guess Ill just use my best estimate and a little lock-tight. Thanks

My original nuts were the type that are self locking and won't back off. You don't really want to go further than snugging up the rubber. The shackle joints are not designed to resist pivoting.

Yes,that's a good point. Use crown nuts.