[VAL] vexing plumbing leak

[Chris Koehn <timberguides@xxxxxxxxx>]

I've been stewing about an intermittent plumbing leak in our 1979 Int'l 
Sov. 31'. Now is the time for action!
The leak manifests when the system is pressurized (indicating it's on 
the supply side I bet) by a drip from the curb-side wheel well where 
the plastic wheel well overlaps the steel framing. No pipes accessible 
from the inside of the coach show any signs of a leak. I removed the 
low, curved section of aluminum skin just in front of the wheel well 
and behind the step, hoping I could catch site of the culprit, but 
alas, no luck.
I'm now contemplating removal of the belly skin (which appears to be a 
real PIA) or the plastic wheel well. Looking for advice on:
A) a probable culprit, and it's most likely location on our particular 
coach;
B) the best plan of attack- remove the wheel well? How does that work? 
Remove the belly skin- or part of the belly skin?

Thanks!

Chris Koehn