I drained my rear air tank today. Yuk!

[crazycal]

This black stuff came out. I thought no big deal, but I put my finger in it and it felt like oil. So I smelled it and it smelled like oil. So finally I tasted it and it tasted like oil. So I figure it must be oil. Right? Now the question is. Is it likely my compressor is leaking and putting oil in my brake lines? How serious is this?

[crazycal]

A truck parts place is probably the cheapest. You might look online.

[oldog12]

Is it likely my compressor is leaking and putting oil in my brake lines? How serious is this?

I'm no expert, but I did sleep at a Holiday Inn Express last night....

Most air compressors draw their lubricating oil off the crankcase, this lubricating oil invariably gets into the compressed air line and condenses somewhere along the line... This, in my opinion, isn't a great cause for alarm, well, depending on the amount of oil you're talking about. Just like the brake fluid in a hydraulic brake system, that oil that you've discovered, doesn't actually get in contact with the actual brake...

That's the way I figure it... But check with someone who is a little more experienced with air brakes... Like a mechanic...

[Elliot Naess]

The compressor will always pick up a little bit of oil and send it into the air tanks. If the
tanks have not been drained properly, REGULARLY, you might get quite an oil bath,
yes. Lots of water too.

After I bought Millicent and drove her home and then drained all four tanks, I
expected the Environmental Protection Agency to knock on my door any time.
Seems the district had broken one of the drain valve pull cords and just neglected
it ever thereafter!

So just drain all the tanks, and keep draining them after every day of driving. And
see how that goes.

[crazycal]

My air tanks have twist valves that were covered with grime. I don't know how long it had been since the school owned the bus, but those tanks had not been drained in quite some time. With that type of valve, there is no way a bus driver is going to climb under the bus to drain the tanks. I will replace them with valves that have pull cables. Much easier to drain daily.

[Elliot Naess]

Yes.

Or install an "air dryer" which expells moisture and oil automatically. But that costs real money.

[the_experience03]

Elliot is back!

Thank God my system has a heated air dryer because I have the dumb twist valves as well and mine are both on the inside side of the tank making them a pain to get to. I try and get to mine daily, but that doesn't mean it always happens. I have yet to find a trace of anything in the tanks.

[Elliot Naess]

Golly, I was only gone a couple of weeks! But I do appreciate the love!
I've found just a few groups of folks on the internet that seem worth hanging out
-- "virtually" -- with, and this bunch is on that short list. Some groups out there are
incredibly rude and quarrelsome!

It's worth repeating: Air dryers really work. In 25 years of stumbling around the
countryside in 18-wheelers on and off, I don't think I've driven a single one that
didn't have an air dryer.
I call it the "sneezer", because it makes a sneezing sound when it dumps the
oil-and-moisture. This device is about the size of a five gallon bucket. It spits
out a bit of air, carrying the moisture and tiny bit of oil, each time the
compressor cycles (as determined by the pressure regulator).

[Excalibrate]

When I first brought my bus home I noticed the air gauge didn't work properly. Not good on air brakes (imagine running out of air on a steep grade and having the wife scrape you off the front window with a spatula!) but i found after bleeding the air a couple times everything worked fine. Like the man said, definately bleed those ever day you drive it.

[swinada]

since I'm pretty new to this and airbrakes (I made my airbrake ticket about 10 years ago and since then never have used any airbrakes)
could someone maybe give me a quick run down on what to do to bleed the tanks properly?
I now i have 4 tanks and seems that somebody installed levers to the outside of the bus to open the tanks. At least I have 2 levers on each side of the bus which when you turn them air escapes from the tanks.
So after driving for a day, do you open them all wide up and bleed them till they are totaly empty? or will a few short spurts be enough to clear out any water / condensation?

[the_experience03]

I always just drain mine completely. It sets the parking brake for good for the night and gives me a chance to check my compressor times in the morning.

[swinada]

what are normal compressor times? How long is to long, to get it back up to 120?