my problem is not the 39-317 part you recco but it is the second arm and slide assy of that combo that is the 5.5" gold arm in the picture on your web site that says Del Mar Toronto on it and the left side bottom and the silver metal base that the window slides on is 11.5" long. The top part is fine. Only the bottom portion is cruddy like the one in the picture.
It is almost black and the hinge that attaches to the bottom of the Silverline Casement Sash was corroded immobile and in fact broke off from the attaching stud on the sash.
I also want to replace the right side casement parts so would need both bottom left and right bottom parts. Tops are clean. Can you help?
I have a photo I took with cell phone but not sure how to attach it. Give me an emailthat will go to you and I will send.