air governor

[davidb56]

I forgot how to test the air governor without removing it from the firewall, which I replaced a couple years ago. My truck isnt building up air pressure at all. It just happened a few days ago after a cold spell. My Bendix DB-9 air dryer inlet is a PITA to get the line off and see if I got flow to it. I heated both the dryer (it also has a 24vdc element at the purge) and the Governor with my propane torch. So now its time to test stuff. I also cracked the discharge line on the compressor and a little air was bleeding out.

 

[NDT]

It takes air pressure to unload so if there is none, the finger points to the sneeze valve on the dryer

 

[Mullaney]

I forgot how to test the air governor without removing it from the firewall, which I replaced a couple years ago. My truck isnt building up air pressure at all. It just happened a few days ago after a cold spell. My Bendix DB-9 air dryer inlet is a PITA to get the line off and see if I got flow to it. I heated both the dryer (it also has a 24vdc element at the purge) and the Governor with my propane torch. So now its time to test stuff. I also cracked the discharge line on the compressor and a little air was bleeding out.

.
The sneeze valve that @NDT mentioned will sometimes get stuck partially open. Squatting down there beside the dryer lets you hear it "hissing". Stick the flat palm of your hand over it and often times it will seal itself shut - then start functioning like it should. That isn't a permanent fix, but it will often times push a little piece of crud out in your hand. That could fix it temporary...

 

[davidb56]

no air bleeding out the purge/sneeze valve. I'll have to take the inlet hose off after I plow today

 

[davidb56]

there was a ice cube about 2 inches long in the air supply line at the air dryer. If I used copper, instead of that famous plastic/nylon crap, I could have heated it up yesterday with my propane torch instead of laying on the frozen ground becoming a ice cube myself.

 

[rustystud]

there was a ice cube about 2 inches long in the air supply line at the air dryer. If I used copper, instead of that famous plastic/nylon crap, I could have heated it up yesterday with my propane torch instead of laying on the frozen ground becoming a ice cube myself.

Well what are you doing with that much water in your air-system in the first place ?
OK, just giving you a hard time, but really the nylon lines are better than the old copper since they will not break due to age hardening and vibration. Plus hit a nylon line with a rock and it usually just bounces back into shape while a copper line will have a hole in it, or get seriously compressed shutting off your air.

 

[davidb56]

Well what are you doing with that much water in your air-system in the first place ?
OK, just giving you a hard time, but really the nylon lines are better than the old copper since they will not break due to age hardening and vibration. Plus hit a nylon line with a rock and it usually just bounces back into shape while a copper line will have a hole in it, or get seriously compressed shutting off your air.

good question....and then Bendix does nothing to prevent it since its before the inlet. My compressor intake is piped to the air filter housing. Must be the weather here.

 

[rustystud]

good question....and then Bendix does nothing to prevent it since its before the inlet. My compressor intake is piped to the air filter housing. Must be the weather here.

How do you have your air-lines running to and from the "wet tank" ? Normally the air compressor feeds the wet tank on any truck in the Pacific Northwest. Then the wet tank sends the air to the "air-dryer" , then the air goes to the main storage tanks.
If your wet tank is freezing up, then it's probably too far from the air compressor. Air from the air compressor is pretty warm for the first few feet, then it cools down pretty fast. So, if your wet tank is close enough to the compressor it stays warm and allows ice free air to enter the air-dryer. If your still freezing up that air-line then wrap the line with insulation to the wet tank, and on to the air-dryer if needs be.

 

[davidb56]

compressor straight to the air dryer, then to the first tank, then the second. that was according to the instructions that came with the dryer. Im going to add a "T" right off the compressor with a cap so if I ever need to add a little Bacardi 151, it will be easy to do. the Nylon line to it is just coupled where the copper line originally went into the first tank. even if I swapped it to copper, its out of the way from potential damage as the dryer is mounted high up on the inside of the frame. But I got too many projects at the moment. I just need the truck to apocalypse plow right now, so I'll leave things like they are and remember where my issue was at if it happens again. BTW there is no "wet tank" on this truck, just 2 main tanks and the dryer is before both those, right off the compressor about 10 feet away.

 

[rustystud]

compressor straight to the air dryer, then to the first tank, then the second. that was according to the instructions that came with the dryer. Im going to add a "T" right off the compressor with a cap so if I ever need to add a little Bacardi 151, it will be easy to do. the Nylon line to it is just coupled where the copper line originally went into the first tank. even if I swapped it to copper, its out of the way from potential damage as the dryer is mounted high up on the inside of the frame. But I got too many projects at the moment. I just need the truck to apocalypse plow right now, so I'll leave things like they are and remember where my issue was at if it happens again. BTW there is no "wet tank" on this truck, just 2 main tanks and the dryer is before both those, right off the compressor about 10 feet away.

If you look at any over the road truck that runs in the Pacific Northwest, you will see the air-compressor line goes to the "wet" tank first.
This is because the amount of moisture coming out of any air compressor will overwhelm the air-dryer.
Taking outside air and compressing it causes heat which causes moisture once the heat dissipates.
That is why you must drain the wet tank every trip.
Our military trucks have a "dual" tank as the first one in line. That is your wet tank.
So, changing the topic a little, how are you liking this early snow ? We got a total of 12" out here. We live in the foothills, so we get snow every year here. Right now, there is over ten inches of snow, but thankfully it is starting to melt.

 

[Floridianson]

compressor straight to the air dryer, then to the first tank, then the second. that was according to the instructions that came with the dryer. Im going to add a "T" right off the compressor with a cap so if I ever need to add a little Bacardi 151, it will be easy to do. the Nylon line to it is just coupled where the copper line originally went into the first tank. even if I swapped it to copper, its out of the way from potential damage as the dryer is mounted high up on the inside of the frame. But I got too many projects at the moment. I just need the truck to apocalypse plow right now, so I'll leave things like they are and remember where my issue was at if it happens again. BTW there is no "wet tank" on this truck, just 2 main tanks and the dryer is before both those, right off the compressor about 10 feet away.

Correct old systems wet tank . Newer systems no wet tank and air dryer between compressor and first air tank. Called ADIS and it's just plumb up as per instructions. My 1992 M915A2 has the ADIS system so they have been in using on air brake systems for decades. Also no liquid alcohol in system that is not how the alcohol whiffer system works.

 

[rustystud]

Correct old systems wet tank . Newer systems no wet tank and air dryer between compressor and first air tank. Called ADIS and it's just plumb up as per instructions. My 1992 M915A2 has the ADIS system so they have been in using on air brake systems for decades. Also no liquid alcohol in system that is not how the alcohol whiffer system works.

Yes the manufactures are going to new styles of "air-dryers" like the "Bendix AD-IS" system, but according to Bendix it didn't come out until 2007. That means it hit the market. Doesn't mean it was in wide spread use. According to an article in "Fleet Owners" magazine dated 2005 the industry was coming into information about newer style "air-dryers" .
Before I left the Transit department, we had several buses that had "experimental" air-dryer systems installed for evaluation. They where the newer style that had the air compressor line installed straight to the air-dryer. They cost several thousands of dollars.
So, no one has been using the AD-IS system for decades, as it hasn't been out that long. In fact, I would be surprised if more than a quarter of the trucks on the road now even have this type of system on them.
I'd be even more surprised if David's truck has this type of system on it. Unless David himself installed it recently.
I checked on the cost of a new "Bendix AD-IS" unit and they range from $400.00 to $800.00 depending on the model and options.
Considering all the problems these units have I would just stick to the good old tried and true "Bendix AD-9" unit and plumb it in after the wet tank. Mine has worked for years now with no problems as have all the ones I worked on for decades have. At this stage in my life , dependability in my equipment is prized above all else. I just want things to work.

 

[Floridianson]

While the little newer ADIS system the DRS - dry reservoir system has been out even longer. He might have that type.
Both air dryers are good systems and installed before any air tank. Would say most OTR trucks or any air brake truck would have one or the other system installed. Even some of the military trucks had DRS. My info has it at the year 1999 for ADIS systems and have been worked out. Bendix Commercial Vehicle Systems - Bendix® Air Treatment

 

[Floridianson]

Sorry something went wrong last post. My info has ADIS and the problems have been worked out. Bendix Air Dryer Problems Could Cause Low Brake Air Pressure - Safety & Compliance - Trucking Info. On a side note when all else fails follow the directions has always worked for me.

 

[davidb56]

well, I plumbed it according to instructions. its fine now. if it does it again, ill replace the 36 inch nylon line to copper, then I can heat it if needed. problem solved. its high enough not to get damaged from brush and debris.But first I'll rewire the internal bendix heater to come on when the 24vdc power switch is turned on to run, instead of the momentary one its on now. Maybe the heat will transfer up to the supply side and keep it clear, since the ice was right at the nylon supply tube right near the fitting. BTW my truck stops fine without air........just stomp on the pedal harder like if there was a rattle snake under my boot again.

 

[rustystud]

well, I plumbed it according to instructions. its fine now. if it does it again, ill replace the 36 inch nylon line to copper, then I can heat it if needed. problem solved. its high enough not to get damaged from brush and debris.But first I'll rewire the internal bendix heater to come on when the 24vdc power switch is turned on to run, instead of the momentary one its on now. Maybe the heat will transfer up to the supply side and keep it clear, since the ice was right at the nylon supply tube right near the fitting. BTW my truck stops fine without air........just stomp on the pedal harder like if there was a rattle snake under my boot again.

So you did buy one of the newer AD-IS style air-dryers ? With our high humidity climates these newer style air-dryers do not do so well. At Metro we had nothing but problems with ours. They had to be rebuilt every week due to the high moisture in our air. Clogged them up really bad.
Took an average of 4 hours to rebuild them instead of the 1/2 hour to rebuild the old Bendix AD-9 .
Don't know what happened to them though as I left not long after that. I did rebuild two of them myself though. Real pain in the butt.

 

[davidb56]

no. I have the Bendix DB-9 . a cheap, but new one I bought on eBay.

 

[rustystud]

no. I have the Bendix DB-9 . a cheap, but new one I bought on eBay.

I'm surprised they said to install it straight from the air-compressor ? That's just asking for trouble especially in our climate.

 

[davidb56]

I'm surprised they said to install it straight from the air-compressor ? That's just asking for trouble especially in our climate.

where else would you install it? I got the compressor, governor, and 2 air tanks in series. I assume the air dryer's job is to remove the moisture before entering the air tanks. I could install it after the air tanks and just bleed off the moisture manually like I do out of habit before I got the dryer.

 

[davidb56]

where else would you install it? I got the compressor, governor, and 2 air tanks in series. I assume the air dryer's job is to remove the moisture before entering the air tanks. I could install it after the air tanks and just bleed off the moisture manually like I do out of habit before I got the dryer.

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