Is anyone familiar with the pressure regulator valve? (the black valve that sits on top of the plastic tank). This valve has a small filter internally which appears to be clogged. Could this clogged filter make the valve alternately raise the car to high level and sometimes allow no pressure to the aluminum valve next to it? If I take a line loose, even though there is no pressure, and then reconnect it, it then operates properly for a short time. Is there any literature available on the workings of this pressure regulator valve. I have replaced it twice in the last six months at a cost of $800 each time. I think it is something simple, but am at wits end(what little I started with). Any advice would be extremely appreciated.