[Lynn Eades]

you could work out the shim pack before you install the seal. I would set it up with a nice easy to turn feel, slightly on the preload side of zero preload (so that it cant move out of alignment under load) It should turn smoothly and easily. This will need to be done with the sector shaft (shaft and peg) lifted clear which will require removal of the box from the carrier.
Of course non of this is achieveable unless the components are in good condition.
There is probably a mark on the spline of the sector shaft that needs to be aligned with a mark on the vertical tube it fits into.