Draining your Air Tanks

[Gary Hatt - Publisher BCM]

All modern buses have air system and all have air tanks.  How often do you drain your tanks?

Asking for a friend. 

[richard5933]

We have no air dryer on our bus - I drain all the tanks at the end of every day the bus gets driven. Takes about 2 minutes to walk around and do the 5 drains, 3 minutes if I forget to do it before I connect the shore power cord which blocks one.

[dtcerrato]

Haven't had any moisture out of our tank drains since we installed a drier.

[Ed Hackenbruch]

Did mine the same as Richard, had cable pulls on all of them.

[lostagain]

Like Dan said, with a good functioning dryer, the tanks don't need to be drained very often at all. Older buses have a "ping tank" just downstream of the compressor that needs to be drained every day, particularly in winter.

[chessie4905]

I installed a Bendix AD9 on mine last year to go along with rebuilt braking system except for brakes at wheels. Thats next. Got my new take off rear drums and lining now. Just need to get the studs and nuts for aluminum wheels. I'll be calling Luke soon.

[luvrbus]

Like Dan said, with a good functioning dryer, the tanks don't need to be drained very often at all. Older buses have a "ping tank" just downstream of the compressor that needs to be drained every day, particularly in winter.

LOL now JC on your new ride you just push the button on the dash that says "Air Purge" and all is good

[lvmci]

In the desert southwest, its pretty dry, I purge more often if driven to the coast. And I purge after each trip, is that often enough when humidity is under 10% JC? lvmci...

[twochain]

We have an AD9 on our 4104.  I do drain the tanks every night when we stop.  We do not have an issue with moisture but to it as more of a safety precaution.  The kids like to pretend to drive when we are resting or stopped and do not want them to release the spring brakes (driveline parking brake removed).  I do place a wheel chock out when only stopping for a short time and tell the kids that they can drive when we stop for the night.

[lostagain]

Tom, do you see moisture come out of your tanks when you drain them? If not, your air dryer is doing it's job. If yes, maybe you should replace the desiccant cartridge in it. It is an easy job that should be done regularly as preventive maintenance. 

[chessie4905]

If you have any oily residue coming out, leave the drain open overnight to completely drain as per GM service manual.

[Friday1]

I have an air dryer on our 4106 but many times if I am working on the bus at home I charge the air system from my shop air compressor   to get it up on the air bags or to use the throttle or so it will shut off when I kill the master switch. That air will by pass the dryer and stay in the front tanks so I have an auto ejector on the front tanks, and a lanyard to pull in the driver compartment.

[dtcerrato]

Our electric auxiliary air compressor is plumbed into the bus air system at the main engine compressor discharge muffler so it travels through the drier also.

[TobyU]

I never drained mine until I had a freeze up the 2nd winter I owned it...then I drianed them frequently. Also started adding alcohol to the dryer canister (MCI .

[Dave5Cs]

Careful with the Alcohol in your air system it will mess with the rubber parts in the system.