How do you get to the shaft seal to replace it ??? My pump is leaking around the seal. I have an A. O. Smith 1 1/2 hp above ground swimming pool pump.

Your motor is AO Smith, your pump is attached to it. You will have a steel band clamp around the pump behind where the basket is, or a large lock ring, or it may go together with six or eight bolts or screws. Don't take off the four bolts that hold the motor to the pump.
after you pull this clamp or bolts it will seperate easy enough. If you have a lock ring and the pump runs undo the ring and start the pump for a second and it will come apart.
Inside you will find a difusser this will ether just pull off or will be held on with two to five screws. Pull this off, now you are at the impeller and you need to look in the center of this to see if it has a screw or a nut in the center. Not all will have this but now days a bunch do, so if you don't see one don't worry. This will be left handed so to unscrew you will turn it clockwise.
Now take a wrench and hold the shaft in the back of the motor, usually a 7/16" open end, (be sure that the power is off for this) then try to unscrew the impeller, you may have to put a screw driver blade in the impeller and give it a hit with a small hammer or the like to get it started. Once you unscrew the impeller you are at the seal just pull out and lube the new one as you put it in. If you can't find the brand of pump take the lid to the store with you and they can get you the proper seal with that. Good luck.