Tuga,
I was under the impression that the elastic material of the valve seat was what failed. I think Richard has some great posts regarding testing and how he learned to replace the seat and stop the leaking. Fortunately I have not had to deal with leaks at the manifold so far.
I think it is reasonable to start with the DOWN solenoids. If the UP leaked you would have at least the pressure of your auxiliary air in the bags. If the TRAVEL leaked the Height Valve should shutoff and stop flow when the coach reached travel position and not go all the way down.
I suspect we all may have slightly different valves that add to the confusion. I have attached a few images to get a discussion going. One shows a spare 6 valve manifold I picked up from eBay for a good price thinking it would be very similar to mine. The schematic was posted on the forum some time ago and I just added some arrows to remind me which way the air may flow. Good luck.
|