[BusNit]

I washed the engine bay (Three day process of soaking and rinsing with garden hose pressure) When I was done I noticed the left side of the coach loses air overnight and leans over. Can't figure it out. Right side holds well. Service brake pressure holds air fine according to gauge. Any ideas where to start looking? There must have been over an inch of caked on dried grease on the bottom side of the engine/transmission.

[Fulltiming]

Might check to see if the air shifter solenoid on the side of the transmission is now leaking.

[BusNit]

Thanks Micheal, I did spray bubble solution on everything back there and have not detected any major leaks. I say major as there is one fitting I tightened down that has minor teensy bubbles of no concern. After tightening some known leaks, the coach does lean on the left side. Everything is fine when the engine is running otherwise. Takes about 3-4 hour before it is noticeable with the engine off. Aux compressor does not help if I leave it running. Coach will still lean over

[BusNit]

I went out to check on the coach. Of course it is completely down on the left side yet the right side is at normal height. So frustrating. I rechecked the 6-packs at the rear and found no leaks. I have an appointment to get an estimate on replacing all the fuel lines since they are hardened. I notice there are a few 3/8" cloth covered air lines that are hardened too but none are blowing bubbles when I soak them with solution.

[Fulltiming]

Is the coach in level or travel mode when it leaks down. If it is in travel mode, the left rear ride height valve would be a candidate as the plastic body can crack. If it is in level mode, the ride height valve should not be in play.

[BusNit]

Thanks for the response! It is in travel mode as I left it there. When the coach is off and it leans over, using the HWH to air it up, it makes no difference as it will not lift that side up. I do not hear any air leaks. I will start the coach tomorrow and let it air up and spray the height valve. Interesting as I didn't make any attempts to get water in that area, but it just could be coincidental.

[BusNit]

This morning the left side was flat on the bags. I started it up and once aired, Got under and sprayed everything I could find. No signs of leaks. Could the rear 6-packs be leaking internally causing the lean? They appear to have been replaced at one time. I was greeted by a 4" Black Palo Verde beetle seeking refuge near the tag tire. Wasn't a pretty sight as my startled look almost gave me a panic attack with a bus 3" above my chest! Needless to say, he was looking to make a friend and kept crawling towards my face!

[Richard]

Ok, you need to make the air leak isolator apparatus. You can search for the threads, but in simple terms

Air line, tee with a 150 psi gauge, quarter turn valve, tee with a 150 psi gauge, air line. Disconnect the air line from the six pack and put the apparatus between the six pack and the afore mentioned line to the air bag. Crank the coach up, open the quarter turn, and let it come to ride height. Close the quarter turn.
Turn of the engine. Wait.

The gauge that leaks down will tell you if the leak is in the six pack or the air tank/air bag. Otherwise you are guessing. You will save yourself a lot of time, aggravation, and money by properly diagnosing this. If the coach stays up with the quarter turn closed, you know the air bag and tank are OK, and the problem is the six pack.

Your aux compressor may not lift the rear of the coach. It takes about 110 psi to lift the rear. Or the leak may be greater than the supply capacity of the aux compressor.