Air compressure

[cadillackid]

sounds like the heater in your air dryer is the issue.. now that its warm is it all working normally? you should be losing pressure when you apply the brakes thats normal.. when the pressure drops below the governor set point the compressor kicks back in and recharges the system.. the air dryer purges (Shhhh sound) when the governor turns OFF... there is a replaceable heating element in the bottom of the air dryer.. make sure you have power to the heater wires whenever the bus is turned on.. they will be the only wires going to the air dryer.. some have a singke wire and then assume the dryer is bolted to ground, others have a 2 pin connector..

its pretty common for that heating element to burn out over time.. or the fuse to pop and cause the wire to have no power..

the element is powered anytime the key is 'on', it has a thermostat to turn it off in warm weather..
-Christopher

[cadillackid]

Originally Posted by Robin97396

Just for clarification it was the failed air dryer that was bleeding off your pressure?

I've been following along, like a couple hundred other people. Feeling your pain with this.

robin - there is a purge valve in the bottom of the dryer.. if that valve freezes its generally as it purges moisture.. when it gets really cold, moisture freezes instantly.. ice builds up, and that valve cant fully close again, result is the air will bleed out of the bottom of the dryer...

you can usually tell if the heater is bad as you'll start to see icicles up and inside the round purge valve hole.. its normal to see a little ice on the very bottom of the purge outlet but not up inside.. thats a first clue that the heater element is defunct (or your dryer is from a warm climate and not heated.. although most of them should be on anything built in the 90s+)

-Christopher

[Robin97396]

Those air dryers are great. We used to hate crawling under the truck to drain the tanks.

[Dead pirate]

Originally Posted by Robin97396

Just for clarification it was the failed air dryer that was bleeding off your pressure?

I've been following along, like a couple hundred other people. Feeling your pain with this.

I believe the failure of the air dryer allowed water to gather in the hoses. When that froze, no air made it to the tank, so no air brakes.

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[Dead pirate]

Originally Posted by cadillackid

sounds like the heater in your air dryer is the issue.. now that its warm is it all working normally? you should be losing pressure when you apply the brakes thats normal.. when the pressure drops below the governor set point the compressor kicks back in and recharges the system.. the air dryer purges (Shhhh sound) when the governor turns OFF... there is a replaceable heating element in the bottom of the air dryer.. make sure you have power to the heater wires whenever the bus is turned on.. they will be the only wires going to the air dryer.. some have a singke wire and then assume the dryer is bolted to ground, others have a 2 pin connector..

its pretty common for that heating element to burn out over time.. or the fuse to pop and cause the wire to have no power..

the element is powered anytime the key is 'on', it has a thermostat to turn it off in warm weather..
-Christopher

The only thing different is there is no ssssh sound anymore. It builds up pressure to about 130 and stays there.

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[cadillackid]

yeah sounds like the internals of the air dryer are dead.. the pressure shuts off at 130 via the governor on the compressor..

the way it works when everything is good, is there is a small hose coming from the governor back down to the dryer.. (along with the large discharge pipe).. that smal hose gets charged with air when the governor turns OFF, this triggers the air dryer to execute its purge cycle. (the SHHH).

on an international you probably have a Bendix AD-4 or AD-9 air dryer, these are no longer manufactured but you can find reman units out there.. . also make sure that smal;l hose from the governor to the air dryer didnt break or crack... its usually nylon.. if the dryer cant purge then the moisture builds up and ends up in the lines and the tanks..
-Christopher

[Dead pirate]

Originally Posted by cadillackid

yeah sounds like the internals of the air dryer are dead.. the pressure shuts off at 130 via the governor on the compressor..

the way it works when everything is good, is there is a small hose coming from the governor back down to the dryer.. (along with the large discharge pipe).. that smal hose gets charged with air when the governor turns OFF, this triggers the air dryer to execute its purge cycle. (the SHHH).

on an international you probably have a Bendix AD-4 or AD-9 air dryer, these are no longer manufactured but you can find reman units out there.. . also make sure that smal;l hose from the governor to the air dryer didnt break or crack... its usually nylon.. if the dryer cant purge then the moisture builds up and ends up in the lines and the tanks..
-Christopher

Thanks Christopher. I can always count on you for the a complete and thorough explanation. At least it won't freeze again for another week.
Ill be in Indy today, and should be able to get it fixed fairly easy. Gotta get out of st. Louis. I always have trouble here. I feel like it's cursed. hehe

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[cadillackid]

you have a few days before we go to the sort-of deep freeze again.. friday night and saturday are possibly going to be a big snow / ice event from indy through columbus, etc.. if you can head southeast a bit like maybe ot the nashville area you can avoid that storm... after storm passage with fresh snow-pack up here (if it hits)we are expecting some single digit nights and teens days for a couple..

you can also see if you can get your hands on any air-brake line anti-freeze.. its an alcohol solution that you can put into the lines if a freeze is expected.. might keep you on the road through it. not sure in st Louis and indy. but i know here in C_bus that 2 weeks of polar stuff cleaned out a lot of retailers of all un-freeze type products... truck stops tend to re-stock pretty quickly though.

-Christopher

[Robin97396]

Is there anybody carrying snow chains? Ive never heard them mentioned and I'm wondering if the tech of having big heavy chains is still the modern tech.

[Brad_SwiftFur]

Originally Posted by Robin97396

Is there anybody carrying snow chains? Ive never heard them mentioned and I'm wondering if the tech of having big heavy chains is still the modern tech.

The school district I bought mine from ever so kindly left the tire chains in the side box.

[Brad_SwiftFur]

Having given this some thought ...

If you are losing 10 PSI every time you use the brakes, I am wondering if your system doesn't have as much reserve as it should? A full brake application might use 10 PSI but not a "normal stop". When was the last time you purged the air tanks? And I don't mean letting the air dryer do it. I'm referring to actually opening the purge valve. A gallon of water in a 3 gallon air tank is bad news. (There shouldn't be any at all, but realistically, never more than a few ounces), this is why daily purging of air tanks is in order.

[cadillackid]

Originally Posted by Brad_SwiftFur

Having given this some thought ...

If you are losing 10 PSI every time you use the brakes, I am wondering if your system doesn't have as much reserve as it should? A full brake application might use 10 PSI but not a "normal stop". When was the last time you purged the air tanks? And I don't mean letting the air dryer do it. I'm referring to actually opening the purge valve. A gallon of water in a 3 gallon air tank is bad news. (There shouldn't be any at all, but realistically, never more than a few ounces), this is why daily purging of air tanks is in order.

my DEV bus has that crappy 3 in 1 tank. so it uses quite a bit of air per stop.. systems with the separate tanks seem to have a lot more capacity too...

-Christopher

[Dead pirate]

Originally Posted by Brad_SwiftFur

Having given this some thought ...

If you are losing 10 PSI every time you use the brakes, I am wondering if your system doesn't have as much reserve as it should? A full brake application might use 10 PSI but not a "normal stop". When was the last time you purged the air tanks? And I don't mean letting the air dryer do it. I'm referring to actually opening the purge valve. A gallon of water in a 3 gallon air tank is bad news. (There shouldn't be any at all, but realistically, never more than a few ounces), this is why daily purging of air tanks is in order.

I'm gonna look, but i don't remember seeing a water release.

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[cadillackid]

almost all air tanks have a little turn valve on the bottom usually at one end.. if you have a 3 in one tank.. there will be 3 little turn valves on the bottom of it..

start the engine let the air pressure build up.. shut off the engine then open those valves.. be ready for a lot of spray of air and moisture..
-Christopher

[family wagon]

Sometimes the tank drain is remote. One of my Blue Birds has a tube drawing from the bottom of every tank and they all come together at a set of valves below the electrical panel under the driver's window. (don't ask me how often I actually open them.)

Air lines are usually taken off the tanks somewhere at or above the mid-line specifically so they'll draw dry air. If you see a line leaving from a port on the bottom of a tank, it's likely a remote drain.

[Dead pirate]

Thanks again you guys. Ill be taking that tomorrow. I bought a mobile compresser just to blow the lines. I'm gonna do the whole mess. Then add anti freezing agent. I've yet to price the air dryer. Im gonna put the volt meter to it first. Holdout it's just the heater.

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[Brad_SwiftFur]

Originally Posted by Dead pirate

Thanks again you guys. Ill be taking that tomorrow. I bought a mobile compressor just to blow the lines. I'm gonna do the whole mess. Then add anti freezing agent. I've yet to price the air dryer. Im gonna put the volt meter to it first. Holdout it's just the heater.

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In all my years of driving air-brake vehicles, I have *NEVER* added stuff like that in the air system. Many road trailers are clearly marked *NOT* to use it as it may damage the system. Most companies don't allow it either, for the same reason.

[cadillackid]

Originally Posted by Brad_SwiftFur

In all my years of driving air-brake vehicles, I have *NEVER* added stuff like that in the air system. Many road trailers are clearly marked *NOT* to use it as it may damage the system. Most companies don't allow it either, for the same reason.

I thought it was OK to add to get rid of moisture and freezing as a one time thing.. ive known people to use it without issue.. just not as a permanent solution.. but as a way to get the system back to Normal after a freeze event..

ultimately the heated dryer needs to work...

-Christopher

[Dead pirate]

Noted

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[Brad_SwiftFur]

Originally Posted by cadillackid

I thought it was OK to add to get rid of moisture and freezing as a one time thing.. ive known people to use it without issue.. just not as a permanent solution.. but as a way to get the system back to Normal after a freeze event..

ultimately the heated dryer needs to work...

-Christopher

Note that I was careful to word my response in such a way that I did not say "Don't use this", only that I haven't, and the reasons for it. It's intended to provide my insight for making informed decisions. I don't want someone coming back in 3 months, saying this caused that, and "Why didn't someone warn me this could happen?"