[Tfrazier]

Hi Chris,
Thanks for the reply. two of the tanks have petcocks and one has a pin that you push to drain. No water in any of the tanks. I have looked in every possible cavity or opening where a tank could be. The two with the petcocks are just forward of the fuel tanks and are pretty close to one another. All three tanks are the same size and oblong in shape.

I searched the overhead cabinets on the drivers and passengers side for the air horn solenoid. I removed all of the panels and covers but didn't find any air lines or anything that looked like it was associated with an air horns. There is a flat screen between the cabinet doors so I suppose it cold be behind the TV. I'll look tomorrow.

I built a leak down tester and I watched the videos on how to use ut. Still not totally comfortable on the process but will start that playing around with it tomorrow.
Tony

[Fulltiming]

Tony, inspect your brake tanks for any pinhole sized leaks in the tanks themselves. I had a couple of those that were draining my air tanks and thus the wet tank was following along as it tried to refill the brake tanks. There are check valves at each of the two brake tanks (the ones in the front) that are designed to keep air pressure up in the brake tanks even if the wet tank is empty. Unfortunately, those check valves can stick and then the air will bleed out of the brake tanks into the wet tank which feeds all the air lines in the coach. Sounds like you have checked the front and rear six packs for leaks. Also check the low pressure valve near the transmission and the pressure sensor for the dash nearby. Since your air horns are under the coach, the solenoid is likely close to the air horns themselves. You mentioned you don't have an air ride seat. I didn't know I did until I found the lever under the front of the seat that locks it down. It had developed a leak and rather than fix it, someone has used a pair of needle nosed locking pliers to crimp the air line to the seat. A big thanks to Richard for locating that mess and fixing it back in 2009. The hoses and valves for the sliding stairwell cover are located in the pass through bay in my coach. That can also be a leak source. Don't forget the air brakes valve near the brake pedal and the parking brake air release under the dash. All of those can leak also. I find that if the air pressure in the coach isn't up to about 100 psi, you can't hear leaks well even with the detector (of course my hearing isn't super). I had a split in the plastic case of one of my rear ride height valves which I couldn't find with bubbles because it was so large that it was blowing the liquid away from the valve. The 120 volt pump has several fittings and of course the worst of all is if you have a leak in the engine driven air compressor hose so that much of the air never gets to the tanks.

Like you, my coach doesn't have many of the potential leak sites such as air operated interior doors but it still has MANY fittings and pipes and dryers and valves and likely many push on connectors.

Good luck in your search.

[Tfrazier]

Michael, really appreciate all of the input. A lot to work with. A bit confused about the air horn..I have air horns on the roof. I'll make sure to keep the air pressure up. I didn't do that today. I set the coach in level mode and raised it to max height before I got it up on the ramps. I left it in level mode. Would that make a difference? Should I have taken out of level mode when looking for the leaks?

Tony

[Fulltiming]

Tony, sorry about the air horn issue. I forgot you have your air horns on the roof so it would make sense that the air line would run up through the upper cabinets above the windshield. Actually, on the level mode vs the travel mode, you need to check it both ways. Different valves are at work. In travel mode, the three ride height valves are activated. In level mode, different solenoids on each 6 pack are used and the ride height valves should be out of the system. Does it hold air in one mode significantly better than in the other mode?

[Tfrazier]

Michael, I will switch it back to travel mode and make sure I keep the air up over 100psi. Will also try see if there are any differences between travel and level modes.
thanks again. Tony

[Tfrazier]

Quick update:

1. I looked under the drivers seat and found a capped off air line. However, I could not find any connection point at the seat. No leak found. Pictures included.
       

2. I think I located the solenoid for the air horn. I was in the center cabinet above the cockpit area, behind the TV. Not leaking but now maybe I can figure out how to fix my air horn. Does anyone know where I can pick up a replacement solenoid?
   

3. Changed over to travel mode and started the process all over again. Right off the bat, I found a few leaks in the compressor bay.
It appears that their is a leak in the body of the Air Control Valve that operates the gen slide. This was noticeable using the ultrasonic and the bubbles (see picture). Question: Can I repair the valve or do I need to replace it? all of the fittings coming into the valve are push fittings but are not leaking.
   

4.Multiple leaks at the compressor: 1/4 turn shutoff leaking. Not visible with the bubbles but very noticeable with the ultra sonic. Also, leak stopped when I closed the shutoff valve.
   

Also air leaking from the black piece (filter?) and lots of air coming out of the slotted area of the compressor. See circled areas in picture.
   

Break is over. Heading out to start crawling around under the coach now

Tony

[Fulltiming]

There is normally a check valve to keep air from flowing back through the compressor. It looks like someone replaced the check valve with a ball valve. You need the check valve in there to prevent air from back flowing through the compressor and out the intake filter, the black item you circled.

[Tfrazier]

Thanks Michael,

Do you have a recommendation on a check valve that I should be looking for or are the all pretty much the same (as long as they are the correct size).

Any ideas on the Air Control Valve?

By the way, I have completed my inspection under the coach, no leaks. I checked all tanks for pin hole leaks and didn't find any. Rechecked the six packs and all connections. No other air leaks that I could find except those in the compressor bay.

Tony

[johnkosir]

There are special check valves for the compressor that bleed off the preasure making it easier for the compressor too start I would not install a ball cable like that in front of the preasure control what happens if you turn off the valve and the compressor gets turned on

[Tfrazier]

Am I on the right track as far as the check valve I need to get for my compressor? Below are a couple of links from Amazon and one from Compressor Source. Will any of these work for my needs?    
Amazon.com: Viair 92833 3/8" Female to 3/8" Male NPT Check Valve: Automotive

Control Devices-PA12-1A Brass Load Genie Unloading Check Valve, 3/8" NPT Female x NPT Male: Industrial Check Valves: Amazon.com: Industrial & Scientific

In-Line Brass Check Valve 3/8" Female NPT x 3/8" Female NPT – compressor-source