I need to replace this pivot shoe

There are a few different ways to replace pivot lock shoes. One way I do NOT recommend but used by some window contractors is to use a heat gun. You can use the low heat setting on a heat gun or hair dryer (be very careful because you can warp the vinyl track if you overheat it, if the vinyl track warps your window will not function properly).

Another way would be to cut out a notch in the track just large enough to fit the pivot lock shoe (again be very careful to only notch behind the window stops located at the top of the main frame for the bottom sash and the bottom of the main frame top sash, if you cut in the wrong area in the track, you will impede the operation of the window).

SWISCO also carries a tool called a jamb spreader 75-069. I highly recommend the jamb spreader, I have used it and I am very happy with its performance. When used properly, the jamb spreader can replace the pivot shoe with no damage to the window track. If you perform any work on your window yourself, always wear safety glasses. If you need help, call a local window repair contractor to assist you with your window repair.

On the aluminum window, first check to see that if there is a cut-out to remove the old shoe. Look behind the sash stops, you will find the sash stops in the top of the inside track for the bottom sash and the bottom of the outside track for the top sash. If there are no cut-outs you will have to make one. Possibly use a type of metal snips or a 'Dremel type tool' to cut the track. However, be careful not to cut too much of the track. Cut just enough to remove the old shoe and no longer than the sash stop so the cut-out will not interfere with the operation of the window. That way when you reinstall the sash stops, you will cover up the cut-outs. Take your time not to damage the window or hurt yourself in the process. Possibly get someone familiar with window repair work to do the job for you.