A quick learner from Angola, IN says:
April 26, 2016
I have an old Pella self-closing patio screen door and one of the wheel/screw ends broke off. It measures around 27" long. What part do I need. Also what are the correct screw sizes to attach the door?
Tom from SWISCO responded:
April 27, 2016
This looks like a Pella trolley. I'm afraid the wheels cannot be replaced by themselves; you will need a new trolley altogether. See our selection of Pella screen door trolley sizes and see if any can work for you. I do not believe these install with screws.