View Full Version : Draining Air Tanks

08-23-2006, 10:32 AM
How often should you drain the Air Tanks on a Frieghtliner and what's the procedure? I read something about pulling some lanyards hanging under the coach. I don't put that many miles on my rig just yet and want to make sure it's well kept.

08-23-2006, 01:11 PM
On the Freightliner XC chassis there are three cables that are looped sticking through the frame behind the front tires. You might have to turn the wheels to the right or left to see them. Should be two on the driver's side and one on the passenger side.

Use the awning pull rod to pull the loop of the cable and hold it for the air to blow out along with any water that has collected in the tank. Do them one at a time. If the air dryer is working correctly, you will get very little water if any blow out. You don't have to completely drain the tank of air, just long enough to blow out any water collected there.

I believe the manual says to do daily, but I usually do it about every 500 miles when traveling or at the end of a short trip.


08-23-2006, 03:08 PM
Ron, Thanks for the info.

Might be a dumb question. Should you drain the tank with air in the bags or out?


08-23-2006, 03:44 PM

No such thing as a dumb question, just sometimes dumb answers. :lol:

I really don't know if it matters, but I have always have air in the bags because of having to reach past the front tires and it is easier when they are inflated and suspension is up.

You really don't deflate the air completely when blowing down to remove the water from the tanks.

The three tanks are 1 for front suspension air, 1 for rear suspension air and 1 for the air brake air, that is why there is three cables connected to a valve for each tank.