jymmiejamz
Adventurer
I understand that isolating the system permits you to indicate front or rear valve block -- but what happens when all four corners go down equally over night? A friend has indicated that the air tanks occasionally leak, but mine pumps back up immediately first thing in the morning, so I am assuming that there is plenty of wind in the tank given that the compressor doesn't always kick in until about 2 minutes after start up.
I would assume you have two leaking valve blocks if the front a rear are leaking down equally. You say you used OEM springs. Does that mean aftermarket? If so I would be suspect of those, especially if from Arnott.
The reason it doesn't make sense for the reservoir to be your problem is because the valve blocks should be isolating the air in the springs from the rest of the system. You should be able to disconnect the air line from the tank and it shouldn't leak down. That being said, tank leaks are common in areas with lots of corrosion, but it will usually set a fault.
I've never done it, but I've been told that you can take apart and clean the valve blocks. They're easy to get to, so it probably wouldn't hurt.