Intermittent AIR Problem

[zubzub]

this is drifting a little but re Nellie's problem, does she get a lot of gunk in her wet tank?  JUst seems odd that she did this awhile back and problems again.  Obviously if the gov is cheap and easy to change start there. 

[Busted Knuckle]

I agree with Lin, new ones are only $20.

$26.00 for a new aftermarket over the counter at an off brand parts place in PODUNK, MS just today! (Sat. 01/16/10) Don't ask me how I know this!
  BK 

And no it wasn't one of my buses, but he was hauling my customers and I was there too and had the tool box!

[gus]

Lin,

When my old type governor failed I just replaced it with the new truck type. The old one was not only strange looking but nothing like the one shown in the manual?? It is mounted high on the firewall, not on the compressor.

As I remember the only difficult part was in figuring out which line went to where because the two governors were so different looking. In the end it did not take long to do the actual connecting and from now on it will be much easier to replace.

[Nellie Wilson]

Hey Zub-Zub, you make a good point.

Jack already picked up the gov. and the unloader kit so, obviously, I'll replace the old. But that still doesn't tell me which failed or why it failed. Next time I air up, I'll give the tanks a good purge. Maybe lay some cardboard down first, make it easier to see what comes out?

To be honest, always been hesitant to bleed those tanks... afraid the valves will never close again
I know, I know... I'm such a wuss.

But I purge my ping tank every time, and never get anything suspicious coming out.

I've heard of guys putting a pull cable on those bleeder valves (to make then accessible). Any thoughts on that?

Nellie Wilson

[Ed Hackenbruch]

 Nellie, i put those on all of my tanks on my 5A this summer. They work great, cost about 15 bucks at napa.  They screw right in, hardest part, (which wasn't that bad ) was routing the cables so they are out of the way. Good cheap project.

[Lin]

Gus,

That was on my last bus that I sold about 1.5 years ago governor and all.  The way you went was probably the best was to do it, but the part was available nearby so I took the path of least resistance.  

[bevans6]

I installed pull cord drain valves on the wet and emergency brake tanks on my 5C this summer (the two tanks between the front wheels).  Valves were $7.95 at Traction.  I routed the cables up and into the fuel tank filler area, I can  drain the tanks easily.  I drilled a couple of holes in the front wall of the fuel tank bay behind the front wheel, up high.

In Canada, DOT daily inspections on air brake equipped vehicles include draining all the tanks (as private vehicles we aren't subject to DOT regulations, but knowing what they are is a good idea).  It probably doesn't get done that often, if you mean draining to zero, but at a minimum the wet tank should be opened up and allowed to spit for 10 or 15 seconds after every day of driving that gets you say 500 miles, and particularly when driving in humid weather or cold weather.  It lets you see what is getting past your air dryer, and in particular lets you see if any oil is coming out.  If you pull the valve and it doesn't seal up again, that's a good sign some junk was in there to block the valve.  it's quite common, even with new valves, that if you drain all the way down they will hiss and leak a bit as the bus starts to air up, until there is a little pressure for them to work against.

Brian

[Nellie Wilson]

Thanks for that Bevans6 -

You made me recall that, yeah, I actually did drain those tanks at one point. And they did hiss and spit for awhile... and I thought "Oh sh**! Trying to do the right thing and screwed everything up." They soon stopped spitting but I never dared touch them again.

Like I said, a wuss!

So - displaying my encyclopedic ignorance - when do I drain them? When they're chock full of air (right after shutdown) or do I let the bus sit awhile first?

And how about that back tank - the one on driver's side just forward of the drive wheels. Mine (MCI) is in a compartment in the rearmost luggage bay. For that matter, how about the accessory tank? Do I drain those too?

Man, all this tank draining is gonna cut into my cocktail hour... thank God for KFC and Dominoes  ...

Nellie

[bevans6]

I would drain them, or at least the wet tank, in the morning before you drive the bus.  The routine is (coffee in cup) approach bus, open the all the engine bay doors, check oil levels, look for stuff that fell off, look specifically for air hoses that may be chafing, drain the ping tank (remember if you stopped the bus while the compressor was compressing, there may be pressure in the ping tank.  If you stopped the bus just after the air dryer purged, there is no pressure at the ping tank.  Big difference in how much stuff comes out and sprays all over your glasses.  I know this from experience...).  Next go up and pull the cord on the  wet tank and look at what comes out  (at least air should come out.  If there is no pressure at all, start the bus and build up some pressure).  If nothing ugly comes out, then I would start the bus, build up pressure and go through the rest of the daily inspection (air brake system checks, lights, lug nuts, tire pressures).

I would drain the dry tank (rear of drivers side luggage bay), parking/emergency tank (curb side between the front wheels) and auxilliary tank (under the drivers seat) routinely.  For me that varies with usage (and on a daily basis "drain" really means open the valve and look at what is coming out, not really drain to the end).  Before and after any long  trip.  Weekly if I am using the bus regularly.  Any time that I am doing maintenance.  If I ever get water out of the wet  tank I pop the drain all the tanks.  I make a point of draining all the way down, in a specific sequence, whenever I am doing a proper inspection of the bus, the equivalent of a DOT monthly or 10K mile inspection.  If you fill and then drain the tanks in a specific sequence you can check and verify the operation of many of the check valves and pressure protection valves, and the emergency brake system. 

cheers, Brian

[gus]

Nellie,

I always drain my tanks when I shut down in the evening while they are still hot just in case it is freezing the next morning. I don't try to drain them when it is freezing.

Carry a spare drain or two since they are so cheap. Some of them can be changed without even getting underneath the bus.

They won't drain very well unless you have air pressure.

More often draining is better than not so often.

[bevans6]

The idea put forward for draining them in the morning is that hot air can hold more moisture than cooler air, so letting the air cool lets the moisture form (like dew overnight) and you get more actual water out.  For me, it's almost moot - you will probably get just as much actual moisture out, in whatever form, no matter what you do.  I  like the idea of doing it as some sort of routine, morning or night, and either can be worked into testing the compressor function, which is about the most important part of the routine.  Doing it at night after running all day has the great advantage of giving you a little time to fix anything you find, rather than putting it off because you were supposed to be on the road a half hour ago, and the pressure will still be high even if your bus bleeds down overnight.

Brian

[buswarrior]

Some philosphic considerations:

If it is below freezing, and there is water in the tank....
Will anything come out when you open the drain?

And:

He who shuts down with compressor unloaded plans to stay until spring?

happy coaching!
buswarrior

[Nellie Wilson]

BW -

I got this one:

"If it is below freezing, and there is water in the tank....
Will anything come out when you open the drain?"

But what does this one mean?

"He who shuts down with compressor unloaded plans to stay until spring?" So, I shouldn't (let it unload) or I should?

If a man says something and there's no woman around...
is he still wrong?

Nellie

[buswarrior]

If there is moisture in the controls for the compressor (governor/unloader/signal lines), or there is moisture in the movement of the purge valve in the air drier...

Which position do you want it all in when they freeze into place?

Hint: You can control too much air with your brake pedal, you can't do anything with no air.

Most of the time, the heat from the passing warm compressed air will melt the lick of moisture in these bits before cut-out, so you are blissfully unaware. A leaky air system that goes to cut-in shortly after shut down has the unintended by-product of saving one's unwitting self from one's self, by moving to cut-in before the pieces get cold.

But if these bits freeze in the cut-out position, there is no flow of warm air, and there will be no melting by the way described above.

The old time drivers who would immediately open and leave the drains overnight also unwittingly set themselves up for success in the morning...if they could get the drains closed again...

I'll leave that last question to those better qualified in the insertion of feet to mouth.

happy coaching!
buswarrior

[Busted Knuckle]

If a man says something and there's no woman around...
is he still wrong?
Nellie

OF course not! But once I thought I was wrong, but it turned out I was only mistaken!
  BK