Moen stop/check valves

I need to replace the stop/ check valves on my Moen tub/shower valve. Are there any special tool I need, and when I replace them I am also replacing the the brass control stem. it is a single handle valve. anything I should be careful for. I have the Moen stem puller

thanks coalmover

Are you talking about the integral stops located on the body of the valve left and right of the center of the valve?