I picked up a basement-dwelling RB-1 this weekend. It's in good shape save for a few problem areas, one of which is a seized BB. I've only worked at the adjustable cup, but it's going nowhere. Just so I know what I'm dealing with - Suntour GPX, we're talking steel cups, right? If they were aluminum, I might resort to ammonia, but w/steel on steel I go with PB Blaster?