I bought one used and the o-ring that came with the pickup (i don't know if its the one RPM provides) would not have sealed it to the motor so i cut the bottom of the factory seal off and made my on o-ring. If you get one you will see what im talking about. I also heard of them falling off so i drilled and tapped another set screw and used lock tight. I was kind of paranoid so i welded a slug to the bottom of the pan so if for some reason it did, it wouldn't fall off completely and i would see a drop in pressure. I havent had any problems .