Brian,
As you know, I use a variety of methods to find leaks, including a stethoscope, soapy water, my ultrasonic leak detector, and finally the Tennessee Bubbler.
While the bubbler is highly effective, it is also labor-intensive and time-consuming. I usually start with the other methods to identify larger leaks, and then use the bubbler to get down to the smaller, more elusive ones. To achieve a level of leak-free like Hector’s, you’ll need to methodically move from fitting to fitting, and device to device, until all leaks are identified and fixed. For example, on my coach, I have the bed lift and dump valve actuators on the same circuit. When testing, I’ll check the whole circuit, find bubbles, and then progressively move downstream, checking each fitting and device.
I might find a few minor leaks along the way, and by the time I get to the end device, the leak rate might be significantly reduced, but it still might not be zero. At that point, it’s up to you to decide if you’re willing to accept a certain level of leak or if you want to replace a valve to get it down to nothing.
As Hector mentioned, achieving a completely leak-free coach can become an obsession, and dealing with leaks can be like chasing “crack.” It’s all part of the fun!