Air leak

[roamer5]

I've noticed that even overnight the coach is losing enough air that the low air buzzer comes on when I start up. Yesterday just for the heck of it I measured the coach height at all four tires ( just in front of the rears and just behind the fronts) and 24 hours later the coach has dropped nearly 3 inches at all four corners. I've crawled all over under the coach with a spray bottle with a soapy water mixture and sprayed anything that looked like an air connection, but can't get any bubbles anywhere. Anybody got any ideas?

2011 Winnebago Journey 40U

[roygfleming]

Did you check the drain valves on your air tanks. A little bit of crud(rust) can get lodged in the drain pin and will slowly leak

[JBDISCOVERY]

Check the air height valve. Small leak can reduce
the height alot.
JimB

[Skip Y]

Same problem. Lose about 40# overnite. Called FRTLNR, who states 'industry standard is 2psi/minute, therefore I'm well within standard!' The air tank blowdown valves are leaking. Squirted Si into valves, then blew them down and manually reseated them which helped, but didn't completely stop leakage. FRTLNR discouraged replacing valves, says they're OK. Will try penetrating oil, then blowing down to try and remove crud.

Skip Y
2010 Journey, 2015 Equinox
WIT Club 47083, FMCA 263635

[TonyMac]

You may have a connection for an air hose to fill your tires. Spray that. You may also have a connection in the front for the tow truck to charge your brakes. Spray that. And you may have a connection in the rear to provide air to a towed vehicle. Spray that too.

[dons2346]

Dropping the same distance on all corners kinda rules out any ride valve.

[96 Wideglide]

Makes no sense to me why Freightliner would advise against replacing leaking tank drain valves !!

[Skip426]

An air system diagram would be a big help , and a little closer look over a longer period of time.

EXAMPLE. The air suspension system on my coach , draws air from one tank , and is isolated from that tank by a " Brake Protection Valve ". The BPV, shuts off air supply to the air suspension at 65 PSI , to maintain pressure for brake application . The two air tanks , are separated by one way flow valves , so an air leak in one will not drop pressure in the other.

So, does the air pressure drop in both tanks or just one ?
Does the air pressure in the tank that feeds the air suspension , drop below 65 PSI ?

Knowing your air system can narrow down your search for a leak , if the one tank drops to 65 PSI and maintains that pressure and the air suspension is right down , then you only have to check the air suspension system for leaks.
If one tank drops to zero PSI and the suspension is down , then you look for your leak , from the BPV back to the tank and at the tank it's self.

[Skip Y]

96 Wideglide, I kinda felt the same way about FRTLNR's comment. They implied it's well within industry std, so it's OK. Also, implied it's helping to drain water from tanks so that's good. At least they made me not panic to replace them, although I think I will at my leisure. Another implication is that those that don't leak have never been blown down, thus tanks haven't been drained (we all know some of those types)

Skip Y
2010 Journey, 2015 Equinox
Wit Club 47083, FMCA 263635

[96 Wideglide]

I think losing air while parked, annoys RV'ers more than truckers !

[AnotherMike]

Originally Posted by roamer5

I've noticed that even overnight the coach is losing enough air that the low air buzzer comes on when I start up. Yesterday just for the heck of it I measured the coach height at all four tires ( just in front of the rears and just behind the fronts) and 24 hours later the coach has dropped nearly 3 inches at all four corners. I've crawled all over under the coach with a spray bottle with a soapy water mixture and sprayed anything that looked like an air connection, but can't get any bubbles anywhere. Anybody got any ideas?

Soap and water requires a good light and that can be difficult underside of RV. What is your time worth? Buy a electronic leak detector. https://www.amazon.com/ALLOSUN-Ultra...s%2C209&sr=8-7 The detector is about $50-$60, is much quicker, and worth every penny...

Mike

[FlatsixV2]

Mike,

Please help me understand the operation of the unit you recommend as it related to finding an air leak.

ie...box inside the motorhome, then follow the air lines and connections with the probe?

Thank You!

[ftodaro]

I just spent a good part of the winter running down air leaks so all of this is fresh on my mind. Let me start out by saying i replaced one of my drain valves its a 20.00 part and took about 10 min. so, just replace it. I went under the coach and listened for air and checked with soapy water, you need to do both. There are a lot of air lines between the tanks and the air bags you want to check all of those connections including the lines going to the leveling valves. I have replaced two leveling vales I had one leaking as it sat in the driveway. You should also check the air bags for leaks. Mine leaked from the bottom side fold in the bag.


Once you figure out whats leaking as its sitting you next want to check the brake circuit, that will be unrelated to the loss of air in the driveway as they are not pressurized.

You want to air up the system turn off the motor and block the wheels take off the Emergency brake. Your looking for and listening for air pressure loss at the rear chambers. Air is used to keep the emergency brake off. I though I had a leak in the rear chambers and replaced them. It turns out my leak was the chime sensor for the emergency brake just above the brake chamber. It was leaking air. An rare failure but i found it.

You will also want to do the standard brake test where you air up the system and hold the brakes on full. After the system settles it should not lose more that 2 to 3 pounds in 60 seconds.

Happy hunting.

[roamer5]

Many thanks to all you guys. I've crawled around under this thing till I've worn the skin off my back, but maybe I'll look a little harder, but maybe I'll take FTL's advice and not worry about it. Again, thanks to all of you.