Hissing sound

[The Enochs]

Ok just drove our 2004 Monaco down to have tires put on. When I pulled up and parked I set the air brake. When I got out I noticed a hissing sound from under the front. The motorhome hadn't been started or driven for 2 months . Any idea what it would be?? A leak or bleed off.

[MSHappyCampers]

Are you sure it's not air escaping from a tire?

The air bleed-off on my coach is at the rear, and it only does this when the engine is running and the air builds up to about 125 PSI. Also, it's only for a few seconds.

[deandec]

Could be your front ride height valve stuck slightly open.

I fixed mine 5 years ago by tapping it with a wrench.....

[YC1]

Ditto on the air ride settling down. Put a few more miles on it.

[Dutch Star Don]

I agree with the above, sometimes one wheel may be setting a little higher and wheel bleed off air. I like to spray the ride height valve assemblies once a year when I do my service to keep them from sticking.