air system leakdown

[snoopy2]

on a 2001 NRV tradewinds LTC/Freightliner chassis,what is considered a normal leakdown time for air reservoirs after dumping air bags with engine off ?

[Gary RVRoamer]

Do you mean how long does it take to dump the air from the suspension? Mine takes about a minute for the coach to drop down pretty much to the stoppers, but I hear a slight hissing at the rear for a couple minutes more.

[Digital Boy]

You are probably referring to your air tanks. You should have 3 of them: two physical cylindars; one having two compartments. Two tanks serve your air brakes. The third captures moisture and is referred to as the wet tank. Your air bags fill directly from your compressor.

If you are losing air over time from your air tanks then you are not following proper airt tank procedure. . . When you finish a trip or will be parked for an extended time, not only do you empty your air bags then level the coach; you should empty all three air tanks as well.

Purging the tanks is the only way to control moisture build-up in your air system. Moisture in your air system will eventually lead to brake damage and unreliability.

I had long chords run from the tanks to just under the front generator access hood. They are color coded. They are within easy reach. I always empty the wet tank first. I can hear the sputter of moisture being expelled along with the air. Then I purge the other two tanks.

You have an air dryer desacant filter that should be changed about every other year. This filter helps control moisture but does not eliminate it from the air system.

I hope this helps.

[snoopy2]

Gary, I was referring to the time it takes for my air tanks to loose their pressure. This is after I have dumped my air bags and leveled the coach. After being parked for 2-3 days, I have lost pressure on the front and rear gauges.

[snoopy2]

Lew, I have bled the air tanks but only about once a year. I have never seen or heard any moisture or spitling from the drains. I live in a rather dry area about 20 miles northeast of San Diego. we don't get much humidity out here. But, I appreciate your descreption of the system. Chuck

[snoopy2]

p.s. Lew, I changed my dryer filters last year shortly after I bought this coach. They apparently had never been changed as there was a lot of muck in the cavity around the coeleasant filter. The coach had 27M miles at that time. chuck

[Digital Boy]

Air up your tanks and air bags. Shut your engine. Take a spray bottle with soapy water and spray all the air line fittings you can find, especially at the tanks.

You might have a loose fitting.

[Gary RVRoamer]

My front tank stays at 75 psi for days, but the rear drops to 0 in about 24 hours. Got a leak back there somewhere.