Updated cab to bracket left then right
After you establish the correct gap for the front mounts and tighten the front bolts down, place a 1" X 4" (which is 3/4" thick) between the frame and the rear cab support bracket, then remove the upper shackle bolts so that the cab rests on the 1" X 4".
Now add or subtract the number of shims on the top of the shackles so that the shackle is flush and install and tighten the bolts through the bottom of the cab.
You should then be able to knock the 1" X 4"s out. If they don't come out easily. add another shim.
