Wet Tank Air Leak Fixed (Accidentally)
Some may remember that I have been, for some time, chasing a stubborn air leak from our wet tank. If I parked the coach in the evening with 100 psi in the air system, by next morning the wet tank would be empty, while the front and rear tanks would still be holding around 80-90 psi. SInce the front and rear tank check valves were working, the leak was obviously in one of the air lines coming off the wet tank. I looked everywhere I could think of, to no avail. I was totally baffled.
Skip forward to our current road trip from TX to Oregon. Our second day on the road, the air system started to act erratically, with the compressor load/unload points drifting up and down. Also, time between unload and load was decreasing, indicating a loss of air that was escalating. Standing at the engine compartment hatch, I could hear air constantly escaping from the purge valve on our AD-9 air dryer. The air compressor was able to keep up with the air loss, but it was working way too hard. I tried adjusting the set screw on the D2 up and down, and it seemed to help a little, but something was obviously still amiss.
We arranged to stay in our current RV park a extra day, so I could work on the problem. Since I was carrying a spare D2 governor and a spare AD-9 (rebuilt) dryer, I decided to do some swapping. I really did not want to get into changing out the complete air dryer while traveling - I much prefer doing that job at home in my driveway. Having done it myself once before, I knew what a pain it was. Instead, first, I replaced the faulty D2 with the new one. Then, I removed the fresh purge valve from my spare rebuilt dryer, and installed it on the coach in place of the malfunctioning valve. When I removed the leaking valve, I found one of the O-rings (the center one) was badly damaged. It had obviously been pinched and torn almost in half when the valve was originally installed in the dryer base. Shows that even genuine Haldex/Bendix rebuilt dryers may not always be totally trouble-free.
Fired up the coach, and the new D2 started controlling the compressor perfectly. The leak from the air dryer purge valve was also totally cured. But the REALLY surprising result became evident after I shut the coach down with 110 psi in the air system. Now, some 6 hours after I finished working, the air system shows 100 psi - on ALL 3 TANKS! Replacing the D2 and the purge valve has apparently cured the wet tank leak! I still do not understand what path the escaping air was taking, but at this point I will happily accept the unexpected bonus!
Topic: Wet Tank Air Leak Fixed (Accidentally)