[cdat]

I've gradually been repairing air leaks on my 91, making fair progress. The rear stays up fine, but now the coach has a tendency to get low in the front, lower on the left then the right. I'm assuming the down solenoid valve might be leaking, but am also concerned that the front supply air tank drain valve might be sticking. Has anyone replaced a air tank drain valve, and if so did you use a spring type, or a petcock?

Thanks for any advice
John