Impossible to find air leak

It does drain both so I'm kind of leaning towards the treadle valve or something in the braking system, that is as long as there isn't a pin hole in one of the air tanks.

 

I've been isolating everything, but no luck so far. I've been using a spray that plumbers use to find tiny gas leaks, it sticks to the surface for hours. $30 a bottle compared to about $4 for Windex.

 

Not where I live just out of Melbourne. We had a couple of days over 100F but today it's cool and raining, about 66F. It's very pleasant down here compared to the rest of the country. Some states are having days of 120.

 

Yep, air operated passenger window, air throttle, air wipers, air start, air suspension. Plenty of potential for leaks but I've isolated all those systems.

 

The airbags stay up for a week, but the main air drops in hour or so. I've found the best way to check for leaking airbags is to disconnect the ride height valves and manually lift the arms so the airbags extend themselves and lift the truck right up until the bags are at their full extension. Then spray Windex around them. The leak is always where the creases are. When you do that, there is around 100 psi in the bags so leaks aren't too hard to find.

 

Now there's an idea haha

 

I just rang up Spectroline who make a very good oil leak detector which I've used in the past. They said yeah, we can sell you an ultrasonic air leak detector.....$6500 for the good one or $2400 for the cheap one hahahahaha