Carl, I think the "liner lock" you are talking about is a piece of rope material that is jammed between the coping and the top of the lip of the liner. I have rope stuffed in 2 of the corners, and multiple coins stuck in the other 2 corners. Does this sound about right for what you are talking about???

Well, after further examination the track piece in the corner is definately broke off. I can see what looks like a piece of cast metal up near the coping that has a 1/2moon break on it, and can feel junk down in the area in the corner between the liner and the pool wall.

Is this something that a novice like me can repair, or do I need to call in an expert????

Thanks,