If the PSS Shaft Seal needs to be removed and re-installed, PYI suggests that you replace the o-rings, and more importantly, change the set screws as they are designed for one time use. This is a replacement kit for the o-rings and set screws.
Here's what comes included with all PSS O-Ring Kits.
Be sure to never use the same set screw on the shaft twice. There are two set screws in each of the two holes in the stainless steel rotor. One is tightened onto the shaft, and the other is tightened onto the first lock it in place against the shaft. The set screws are made with a cup at the base that compresses into the shaft, ensuring a secure grip.