Air Dryer

Joined
Dec 5, 2017
Posts
19
Location
Cincinnati
Has anyone upgraded their air dryer at at least changed the element? Or do you have an air dryer?

I have the Bendix AD-2. Here are my options:

1- Change the element for 50 bucks and clean and service the old unit
2- buy a new AD-9, Haldex, or similar for a few hundred bucks

Can anyone chime in here to what is the stander procedure. Any suggestions and newer models? Problems?

Thanks,
Jay
 
Can the air-dryer cartridges be regenerated?

If they are silica-based then getting them to 250F for a few hours should save $50
 
I don't care to spend the 50 bucks, instead of cooking my current element. I'll have it open anyway. I'm just looking for those who have purchased a new air dryer and the good/ bad.
 
I have an AD-9 on my bus and I personally have not changed the cartridge in it. When I do decide to do it there are a lot of how to videos and instructions out there.
 
In route service, we change the cartridge yearly. Any oil blowby from the compressor will ruin the desiccant, making rejuvination require more then just popping it into an oven for a few hours. Just get a reman one and you don't have to worry about it. Follow the instructions for maintenance intervals on bendix's website if you're unsure of how often to service.

On that note, I've never changed mine on my bus. The air tanks are always dry so I don't see a need to spend the money.
 
In route service, we change the cartridge yearly. Any oil blowby from the compressor will ruin the desiccant, making rejuvination require more then just popping it into an oven for a few hours. Just get a reman one and you don't have to worry about it. Follow the instructions for maintenance intervals on bendix's website if you're unsure of how often to service.

On that note, I've never changed mine on my bus. The air tanks are always dry so I don't see a need to spend the money.

The most I ever get is a slight "misting" when I open the wet tank.
 
In route service, we change the cartridge yearly. Any oil blowby from the compressor will ruin the desiccant, making rejuvination require more then just popping it into an oven for a few hours. Just get a reman one and you don't have to worry about it. Follow the instructions for maintenance intervals on bendix's website if you're unsure of how often to service.

On that note, I've never changed mine on my bus. The air tanks are always dry so I don't see a need to spend the money.

I agree no misting or dripping on tank drain let it be misting or dripping reman cartridge
 
At my shop we service the air dryers annually. These are not too difficult to service and maintain, but upgrading to one with the spin on filter would save way more time down the road.

brokedown, to find the air dryer, simply follow the stainless steel air line (some may be copper or steel) that comes right off the compressor and it goes right to the dryer.
 
Mine is behind the mudflap on the rear end driver's side. That doesn't make sense to me because the air dryer is physically closer to the third tank than it is to the wet tank. Then again if that air dryer was mounted right under the driver it might cause the driver to develop a twitch over a period of time.

Absolutely no hint of water in the wet tank by the way.
 
+1 on replacing the cartridge yearly.. however older air dryers do have parts that fail.. usually it will manifest itself as the purge valve sticking and causing issues at governor cut in.. or a dryer installed in a southern climaste may not be heated and therefore causes freezing in really cold temperatures.. or the heaster element goes bad..

my carpenter bus had a ragged AD-4. so I just ordered a ReMan AD-4. and slapped in there.. and all has been great... it will be due for a cartridege replacement this spring..

,y red bus never had a dryer ands the whole air system froze last winter.. so i installed a Haldex (1250??).. both are heated and ive had no issues with freezing and have very little moisture in my tanks.. both busses hav e new compressors so oil in my tanks is not an issue either..

taking care of your air dryer is of UTMOST importance if you are living in or driving to a cold climate... air-line freezing is real and can cause HUGE issues..
-Christopher
 
+1 on replacing the cartridge yearly.. however older air dryers do have parts that fail.. usually it will manifest itself as the purge valve sticking and causing issues at governor cut in.. or a dryer installed in a southern climaste may not be heated and therefore causes freezing in really cold temperatures.. or the heaster element goes bad..

my carpenter bus had a ragged AD-4. so I just ordered a ReMan AD-4. and slapped in there.. and all has been great... it will be due for a cartridege replacement this spring..

,y red bus never had a dryer ands the whole air system froze last winter.. so i installed a Haldex (1250??).. both are heated and ive had no issues with freezing and have very little moisture in my tanks.. both busses hav e new compressors so oil in my tanks is not an issue either..

taking care of your air dryer is of UTMOST importance if you are living in or driving to a cold climate... air-line freezing is real and can cause HUGE issues..
-Christopher
I don't even know what an air dryer is! Dear Lord what have I gotten myself into!?!?!

Sent from my XT1585 using Tapatalk
 
I don't even know what an air dryer is! Dear Lord what have I gotten myself into!?!?!

Sent from my XT1585 using Tapatalk

It's not something you need worry about until you have your bus home.

Have someone show you how to drain the wet, primary and secondary tanks to blow out any moisture before you drive. Plus the aux. tank if you have one.

It's important, and easy ... especially if you think you might encounter freezing weather. The danger is that your brakes could freeze up, but as I said, it's easy to blow out the moisture and drivers should do it every day.
 
The air dryer is the loud PSSSSSSST that you hear when you're near a diesel vehicle. It blows out moisture if it's working right. Shouldn't be a problem in these temperatures.
 
there is a lot of moisture in air that is compressed into your air brakes tanks.. that moisture can cause issues with brake components, and as mentioned in below freezing weather can cause your brakes to malfunction..

air-brake equipped busses have a device in the system that removes the moisture from the compressed air before it goes into the tanks and brakes.. if you are picking up a bus in the south and driving it to really cold weather pay attention that you hear the 'Shhhh' sound when the pressure reaches 120 on your dash gauge..

most all air dryers are heated so the water in the air wont freeze .. and it usually wont become an issue unless you get into weather below 20-25 or so as the air itself warms up some by virtue of it being compressed..

a bus driven in a northern climate shouldnt have any issues with freezing as the air dryer heater is part of the inspection that is done each year..
-Christopher
 
there is a lot of moisture in air that is compressed into your air brakes tanks.. that moisture can cause issues with brake components, and as mentioned in below freezing weather can cause your brakes to malfunction..

air-brake equipped busses have a device in the system that removes the moisture from the compressed air before it goes into the tanks and brakes.. if you are picking up a bus in the south and driving it to really cold weather pay attention that you hear the 'Shhhh' sound when the pressure reaches 120 on your dash gauge..

most all air dryers are heated so the water in the air wont freeze .. and it usually wont become an issue unless you get into weather below 20-25 or so as the air itself warms up some by virtue of it being compressed..

a bus driven in a northern climate shouldnt have any issues with freezing as the air dryer heater is part of the inspection that is done each year..
-Christopher
Wow, this is a really good explanation! Thanks. The bus has automatic chains and sanders it so it should have a heater. If the mechanics adjusted the air brakes they should have also checked the air heater probably, but I can double-check with them.

But even if something goes wrong with my air brakes the spring brakes are supposed to be able to stop the bus in an emergency, right? I do have two mountains to go over. Not in the Rockies, thankfully.

This forum is the BEST. Y'all are so helpful.

Sent from my XT1585 using Tapatalk
 
Wow, this is a really good explanation! Thanks. The bus has automatic chains and sanders it so it should have a heater. If the mechanics adjusted the air brakes they should have also checked the air heater probably, but I can double-check with them.

But even if something goes wrong with my air brakes the spring brakes are supposed to be able to stop the bus in an emergency, right? I do have two mountains to go over. Not in the Rockies, thankfully.

This forum is the BEST. Y'all are so helpful.

Sent from my XT1585 using Tapatalk
The mechanic said he thought my bus did not have a heater and it IS going to be cold and pretty humid when I drive it over the mountains per the forecast. Advice?

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If you loose air pressure, your parking brake WILL apply with no action on your part. It is a "spring apply, air release" brake. As air pressure is lost the spring overcomes and the brakes apply.
 
And be warned...they can come on rapidly! Many of those long black streaks you see on Interstate pavement are from big rigs losing air.
 
If you hear the low air warning while you're driving you need to pull over as soon as possible. After a minute or two, maybe less, the brakes will apply and you'll stop wherever you happen to be.
 

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