Simonton sliding door rollers clogged with dirt

I purchased a home with a Simonton sliding glass door to the deck. The door has a heavy-duty sliding screen door as well. (Great screen door with large dogs sometimes visiting us.) That screen door has a roller attached to a spring-like piece of metal on the bottom that has broken off. I expect there are 4 of these on the door.

It appears the groove in the roller had gotten filled with some compressed dirt the consistency of slightly dried putty.

I am looking for a replacement roller - possibly a couple of rollers in case of future need.

Can you advise me on this. I coud also use some advice on the best way to remove the screen from the track and then re-insert into the track.

Thanks,

Ed

Attached are the pictures of the the broken wheel that is from the screen track. I am interested in 1) purchasing some replacement wheels for the screen, 2) finding out how to easily remove the screen from the track and 3)replace the wheel.

Thank you...

Ed W