41 degrees is wonderful (Frozen air lines)

belfert · January 06, 2008, 03:28:38 PM

It got up to 41 degrees today. I went out and started my bus and the air pressure actually came up this time. (I also washed the windows on my house.)

I had started the bus last weekend to use it when it was much colder, but the air pressure wouldn't build, and it was fairly obviously the air governer was stuck. I tried heating the governer and rapping it to no avail. I decided to wait until a day above freezing.

I serviced the air dryer last fall, but obviously I still have moisture in the system. Any suggestions on getting things dried out? The rear tanks have some sort of automatic drains, but the front tanks still have the old fashioned pull rings to drain them. I'm not sure the air dryer had ever been serviced in the previous twelve years based on how it looked.

NJT 5573 · January 06, 2008, 03:57:11 PM

Brian, if you change the drains to the petcock design you can drive all day once in a while with one or more slightly cracked open. After a couple of hours they will be flowing warm air and that will dry things out. I'd use some DOT plastic line and move the petcocks out to a wheel well where they are real accessable.

If you remove the automatics from the bottom of the tanks and don't find any water, they must still be working.

makemineatwostroke · January 06, 2008, 04:03:43 PM

belfert you need to check and make sure the heater part of the drier is working

belfert · January 06, 2008, 04:20:31 PM

Quote from: makemineatwostroke on January 06, 2008, 04:03:43 PM
belfert you need to check and make sure the heater part of the drier is working

I replaced the heated purge valve three or four months ago. The bus had last been started in early November before I started it last weekend.

tekebird · January 06, 2008, 05:29:26 PM

Air dryer is not a catch all safety from frozen air lines. Only thing that is is regular tank draining and an alcohol system.

I beleive Ice Road Truckers had a breakdown with a frozen brakes.....with a dryer.

buswarrior · January 06, 2008, 05:38:51 PM

How do you know something was frozen?

Air valves have moving parts inside them, with whatever crap might be in there, old lube, or debris...

The cooler temps might have stuck a valve due to a mechanical issue with thickening lube and be unrelated to freezing moisture.

Old, poorly maintained air systems have more trouble than just water freezing. Many of our valves should be changed out as preventive maintenance.

And that over-dramatized Ice Road Truckers show did not tell any story accurately... breakdowns or conditions!

happy coaching!
buswarrior

tekebird · January 06, 2008, 07:56:35 PM

OK, no Ice road Truckers....but more than one heavy vehicle with heated air dryers have been stranded due to Air Line or Dryer Icing

buswarrior · January 06, 2008, 08:57:16 PM

Thanks tb

Yes, if the heater and the wire to it are not working, the purge valve has a bad habit of freezing open while in operation, which blocks the path of the air from the compressor. So the compressor runs steady, as the governor sencing line is from the wet tank, no air gets through, and the pressure in the line climbs to where pump and its limits are reached.

Open the "drain daily" inside the side engine room compartment at this point in an MCI, and you've never seen or heard it like that before!

Also, this is a real threat to a well maintained and air tight system on shut down. By the time air leaks away far enough for the governor to signal the air dryer purge valve to close, hours have gone by, and it's frozen open. Disabled on start-up.

Solution: behave like the grisled veterans: drain it down on shut down in cold temps, then the purge valve will be frozen closed, and the air system can build, and will cycle properly with the governor, it just might not purge until it thaws.

Oh the joys of winter operation...

happy coaching!
buswarrior

gumpy · January 06, 2008, 09:14:10 PM

As I told you the other day, and reiterated here by buswarrior, it may just be the shuttle in the governor is gummed up by old grease and cold weather. Personally, I'd rebuild or replace the governor now that you've got it free again. Chances are you don't have moisture in the system, but if that governor is original equipment, the lube in it could be very stiff. Mine did the same thing. Only was a problem in the cold. I rebuilt it and it's worked perfectly since.

craig

Paladin · January 06, 2008, 09:57:06 PM

Where is this governor and how do you rebuild? I need to learn this stuff.

Quote from: gumpy on January 06, 2008, 09:14:10 PM
As I told you the other day, and reiterated here by buswarrior, it may just be the shuttle in the governor is gummed up by old grease and cold weather. Personally, I'd rebuild or replace the governor now that you've got it free again. Chances are you don't have moisture in the system, but if that governor is original equipment, the lube in it could be very stiff. Mine did the same thing. Only was a problem in the cold. I rebuilt it and it's worked perfectly since.

craig

Dallas · January 07, 2008, 04:26:19 AM

Quote from: Paladin on January 06, 2008, 09:57:06 PM
Where is this governor and how do you rebuild? I need to learn this stuff.

Quote from: gumpy on January 06, 2008, 09:14:10 PM
As I told you the other day, and reiterated here by buswarrior, it may just be the shuttle in the governor is gummed up by old grease and cold weather. Personally, I'd rebuild or replace the governor now that you've got it free again. Chances are you don't have moisture in the system, but if that governor is original equipment, the lube in it could be very stiff. Mine did the same thing. Only was a problem in the cold. I rebuilt it and it's worked perfectly since.

craig

This is the D-2 Air Governor that you have.
They cost about $20 new but many times can just be cleaned out with brakeKleen to make them operational again.

belfert · January 07, 2008, 04:52:00 AM

Quote from: gumpy on January 06, 2008, 09:14:10 PM
As I told you the other day, and reiterated here by buswarrior, it may just be the shuttle in the governor is gummed up by old grease and cold weather. Personally, I'd rebuild or replace the governor now that you've got it free again. Chances are you don't have moisture in the system, but if that governor is original equipment, the lube in it could be very stiff. Mine did the same thing. Only was a problem in the cold. I rebuilt it and it's worked perfectly since.

I do plan to replace the governer. The issue right now is getting to it. It was not a good idea to put the house batteries where the bathroom and A/C compressor where next to the engine. I have plans to relocate the batteries.

This whole project is something that will have to wait until warmer weather.

buswarrior · January 07, 2008, 07:22:00 AM

Anything with moving parts that are old to begin with, and then go dormant, like the operation of a bus conversion.... or the busnut....

Won't move properly when called upon to re-enter normal service.

The air compressor governor, as illustrated in Dallas's post, is one of the cheapest air system relibility maintenance a busnut can do.

And one of those swap-it-in remanufactured air dryers, ($170 around here this past fall) and then the condition of purge valve, desicant, heating element, are all known, you only have to be sure you have a good wire running to it.

Doing those two, and most busnuts will be set for the next 10 years, if you really want to...

happy coaching!
buswarrior

belfert · January 07, 2008, 08:24:21 AM

I am going to replace the air governer when the weather warms up for more than a day which will be a few months. The only things I have not replaced on my air dryer are the baseplate and the cover.

I haven't seen anyone selling reman AD-9 dryers as cheap as $170, but I probably wasn't looking all the right places. It would have been less expensive back in September to get a new one instead of reman as new ones were on sale.