Strange Aux behavior

I have observed some curious behavior lately by my auxiliary compressor.
I am happy to report that I have cured enough leaks to the point that my aux compressor now cycles maybe once a day or so. This is after about a year of leak chasing and curing.
HOWEVER; after each of our last two day trips when we returned and let the coach down, the aux cycles about once an hour. I have checked the obvious old places it leaked and not found any. Now here is the strange part. After about 12 or so hours, the cycling starts to lengthen between occurances and after about 24 hours we are back to our once a day regimen.
Now I know this is somethng simple and eventually it wil be found but are there any guesses that may be available from this fine group?

When you lower the coach you initiate the opening of the three 3 port Norgrens that exhaust air as well as the shifting of the three 5 port Norgrens to open the path from air bags to the exhaust.

If I were to take a guess as to why your aux system is leak free except after you lower the coach I suspect the answer lies in the air circuit that relates to lowering the coach. Going further, unless you tell me otherwise, this only occurs when lowering the coach and the issue goes away when the coach is raised or asked to return to the driving height. That being the case I would focus my attention on the three 3 port valves in the steer compartment, but not rule out any of the 5 port Norgrens that might not be shifting properly, or more precisely not returning to the off or closed position due to weak return springs or something inhibiting motion of the spool.

Good luck because this is the stuff that drives you nuts. The quick check for the 3 ports is to insert a pipe plug and see if the aux compressor all of a sudden goes to a long time between cycles. That tells you the 3 port may have issues, but it does not rule out the corresponding 5 port from being suspect.

If your Norgrens are getting a little long in tooth (10 years or more) they are due for rebuild or replace.