No air pressure

[Floridianson]

As stated before it is just a airdryer can be added to any truck. Nothing to do with CTIS just keeps out the moisture.

 

[drqsack]

Thanks for all of the responses! I did take the the small housing off the bottom with 3 screws. Then there is a bolt on the bottom of a small black plastic circular piece that is about 2 inches in diameter. I tried to uncrew the bolt. It spins in both directions with some resistance but not much. No matter how many times you turn it nothing happens. I then noticed a 2" ring clip holding in the plastic plug. I took that out and pulled on the plastic plug. It came down about 3/4 an inch and then stops. I could keep pushing it up or down but it wouldn't come out. At that point I decided to put it back together and see if the problem was still there. I started the truck and the air pressure was there again. No sounds coming out the hole. When the truck does reach the normal pressure is blows the relief blast right out that hole. So then I went to get some gas. It ran great with very strong brakes. It seemed like the air was relieving itself every 3-4 seconds. The pressure is usually around 120 but at times it drifted between 90 and 120. Then I went to start it up again at the gas station and the problem was back - air was leaking iwith a steady hiss out the bottom and the air pressure fell to about 50 - 60 psi as I pushed on the brake a few times to see what would happen. I was close to home (all farm roads) and knew I wouldn't need the brake that much so I decided to just drive it home. Once I gave it the gas it went back to 120 psi. So I have drove it around town today. Sometimes it hisses and sometimes its quiet. Whenever the truck releases air its always out that hole. I'm not sure what is normal for this truck, I just don't want to get stranded somewhere without any air pressure. I want to put in a bypass valve there in case I get stranded somewhere but that won't work because thats the device the extra pressure comes out. Oh well, I'll keep driving it and see what happens. It sure was fun to finally drive it around. The EUC took 8 weeks ( the auction closed nov 12th ). Thanks for all of the help. Pat

 

[Stan Leschert]

Get thee to a HD truck shop. Any real airbrake tech should be able to solve this for you in a minute. If there is a military base nearby, go bug their mechanics. They will be your best resource, and they are quite often willing to assist. A beer or 2 works wonders!

 

[rwoods]

As stated before this is the air dryer and heater assembly. Check out pages 1218 -1226 of TM 9-2320-386-24-1-1 for maintenance. TM file is too big for me to download for you. Ron

 

[G-Force]

That is the way the dryer works. When the compressor reaches its pressure setpoint and unloads (goes into freewheel mode and does not pump) that valve on trhe bottom of the dryer opens to purge out any moisture that has accumulated in the bottom of the dryer. You can bypass it and nothing will happen. Except you will start getting moisture in your air tanks. I would drop the entire unit and take it apart to see why the dump valve isn't seating. There is also a dessicant element in it that you should probably change.

 

[G-Force]

On the other hand...after doing some research the dryer is only used apparently used by the CTIS system. So if you do disconnect it you'll be putting air that may have moisture in it into your tires. There are several manufacturers listed for the dryer. The one that can be referenced , Haldex, is at this website: http://www.haldex.com
Their part number is: N4250B
Also, I have attached the parts list for the Dryer assembly:
right click and open it in another window.
Have fun!!!!!

 

[Floridianson]

On the other hand...after doing some research the dryer is only used apparently used by the CTIS system. So if you do disconnect it you'll be putting air that may have moisture in it into your tires. There are several manufacturers listed for the dryer. The one that can be referenced , Haldex, is at this website: http://www.haldex.com
Their part number is: N4250B
Also, I have attached the parts list for the Dryer assembly:
right click and open it in another window.
Have fun!!!!!

Well all I can tell you is my A3 has the CTIS system pulling the feed air from the inboard tank. That would be compressor, air dryer then tanks.

 

[G-Force]

Floridason,
I was just going by where they listed the dryer in the parts manual. It was in the section for the CTIS. The way you say it is piped would definitely make more sense.

 

[drqsack]

Thanks for the posts. That manual number is awesome rwoods! I was up hours reading through that. It also helped me narrow it down. Either it is the heating element in the air dryer or the air pressure govenor/regulator on the compressor. The govenor tells the purge valve when to release air through a small air line. The manual says to disconnect this air line at the air dryer to problem shoot it. If air is still coming out of the air dryer there is a leak in the air dryer. If not, and air is constantly coming out the control line, then the govenor is faulty and I need to replace that. Now... how in the world do I find parts for this thing??? I tried to use the part number floridianson indicated above, and could find it on the company site, but I can't find a place to actually buy something. At some point I will need filters and things. I want to replace the filter/canister thing inside the air dryer as well. How would I find a govenor, or air dryer, or filters that I can purchase. I have been driving the truck more ( yes - I totally love it ). It seems to build up pressure good if driving it - higher rpms, but sometimes the pressure fluctuates a lot (with frequent air discharge noises outside), and other times is very steady with infrequent air discharge noises outside. Sounds to me like it is the govenor on the air compressor or ice in the purge valve (heating element not working - the manual shows how to problem shoot it - I just haven't had time yet), not a leak in the air dryer as that would be there all the time. How do I find a govenor? Thanks for all of the help! This site is incredibly useful.

 

[Floridianson]

Nappa bendix 2d governer

 

[fasttruck]

Object is an air dryer and it has an ejection port on the bottom. In cold weather ice will form there and allow air to escape. Most of them have an electric heater to melt the ice. If this does not work air will continue to leak. my commercial truck will ice up over night and it usually trakes ten minutes for the heater to melt the ice to allow air pressure to build.