MCI 102c3 6v92ta Mechanical Won't Air Up

[chessie4905]

look at ports on air drier. did you get them reversed?

https://www.google.com/search?q=bendix+air+drier+ports&sxsrf=ALiCzsaAUtuiE6bWBfI6iy_CfNUCK1THMg%3A1663752942661&source=hp&ei=7toqY73xJfal5NoPyMaMkAs&oq=bendix+air+drier+ports&gs_lcp=ChFtb2JpbGUtZ3dzLXdpei1ocBADMgcIIRCgARAKOgYIswEQhQQ6CAguELEDEIMBOhEILhCABBCxAxCDARDHARDRAzoOCC4QgAQQxwEQ0QMQ1AI6CwguEIAEEMcBENEDOg4ILhCABBCxAxDHARDRAzoOCC4QsQMQgwEQxwEQ0QM6CwguEIAEELEDENQCOgUIABCABDoICC4QgAQQsQM6CwguEIAEELEDEIMBOgsILhCABBDHARCvAToICC4QgAQQ1AI6CwgAEIAEELEDEIMBOgUILhCABDoICAAQgAQQsQM6BAgAEAo6BAgAEA06BQgAEIYDULcNWNhnYNlsaAFwAHgAgAG5AYgBqxeSAQQwLjIymAEAoAEBsAEB&sclient=mobile-gws-wiz-hp#imgrc=I-kNeW8Ou837UM

[buswarrior]

Put down the tools and slowly back away...

You've got your pneumatics and your electrics mixed up in your wetware.

If you have good air at the discharge muffler drain "drain daily" then the compressor is cut-in and pumping air.

The signal lines to activate the air compressor governor and the air drier are airlines, smaller lines 1/4 inch give or take.

One line comes from an air tank supply to the governor, the other goes from the governor to the air drier. They have to be in the correct ports.

The purge valve heater on the bottom of the air drier is electric, and should have been designated the native voltage of the bus chassis, 24 volts for us, not the 12 volts that the trucks use. Whether that takes a single wire or a feed and a return, direct attached or a plug, all depends on the model/vintage of the air drier.

Start over, confirming that all connections are correct, plumbing the drier or the check valves backwards will block airflow.

With everything empty, the air drier purge valve should have returned to closed and should be allowing air further into the system. It has a spring, and is triggered open via a pressure signal. So, even if you screw up and don't put the signal line, it will pump, but won't purge.

Every decision you made installing this, must be revisited, and confirmed correct. Find the mistake.

Happy coaching!
Buswarrior

[Jcparmley]

I believe it has to be the governor because the 1/4 signal line is connected correctly to the air dryer.  I did not do anything with the governor so all lines are still connected the in the correct port.  Would you agree with that assessment?

Put down the tools and slowly back away...

You've got your pneumatics and your electrics mixed up in your wetware.

If you have good air at the discharge muffler drain "drain daily" then the compressor is cut-in and pumping air.

The signal lines to activate the air compressor governor and the air drier are airlines, smaller lines 1/4 inch give or take.

One line comes from an air tank supply to the governor, the other goes from the governor to the air drier. They have to be in the correct ports.

The purge valve heater on the bottom of the air drier is electric, and should have been designated the native voltage of the bus chassis, 24 volts for us, not the 12 volts that the trucks use. Whether that takes a single wire or a feed and a return, direct attached or a plug, all depends on the model/vintage of the air drier.

Start over, confirming that all connections are correct, plumbing the drier or the check valves backwards will block airflow.

With everything empty, the air drier purge valve should have returned to closed and should be allowing air further into the system. It has a spring, and is triggered open via a pressure signal. So, even if you screw up and don't put the signal line, it will pump, but won't purge.

Every decision you made installing this, must be revisited, and confirmed correct. Find the mistake.

Happy coaching!
Buswarrior

[buswarrior]

No, you said you got good air out of the "drain daily" discharge muffler drain?

In which case, the air compressor is pumping, so the governor is in correct configuration.

The way is blocked. Find the blockage that your work has introduced.

It worked before you started.

You touched something, don't make it worse by touching more things, that you didn't touch before.

Happy coaching!
Buswarrior

[Jcparmley]

So I must have plumbed the air dryer wrong? 

Jared

No, you said you got good air out of the "drain daily" discharge muffler drain?

In which case, the air compressor is pumping, so the governor is in correct configuration.

The way is blocked. Find the blockage that your work has introduced.

It worked before you started.

You touched something, don't make it worse by touching more things, that you didn't touch before.

Happy coaching!
Buswarrior

[buswarrior]

Was this a straight swap, or a change in air drier models?

If the in and the out are reversed, the air won't go through.

All the reman plastic dirt plugs were removed from all the ports?

The box it came in, all the papers were inspected and read, as to how to prepare it for install?

Not a lot left to check?

Happy coaching!
Buswarrior

[Jcparmley]

It was a swap out.  I read the paperwork.  I crawled under and took some photos.  I believe I have it installed correctly.  The supply line comes down from the bus floor and into the supply port on the dryer.  The delivery line goes out of the delivery port on the dryer and up and into the two air tanks between the front axles.  The 1/4 control like is connected to the control port on the dryer and the heater is wired correctly. 

Perhaps I need to remove the supply line and turn the bus on and see if it is blowing air.  If it is then something must be wrong with the new dryer or the delivery line to the other tanks is plugged.  Does that sound like a logical step? 

The first pic is the supply line coming from the floor of the bus. 
The second and third pic is the delivery line going to the tanks

Was this a straight swap, or a change in air drier models?

If the in and the out are reversed, the air won't go through.

All the reman plastic dirt plugs were removed from all the ports?

The box it came in, all the papers were inspected and read, as to how to prepare it for install?

Not a lot left to check?

Happy coaching!
Buswarrior

[buswarrior]

Supply and Delivery...

Have you got it connected like the attached diagram?

Loosen off the one you think comes from the compressor and confirm it blows air.

Happy coaching!
Buswarrior

[buswarrior]

An installation manual for the AD9 attached.

Happy coaching!
Buswarrior

[chessie4905]

disconnecting the line and checking for air output is the simplest way to diagnose. Sometimes those airlines take a convuluted path, confusing their origin.

[Jcparmley]

I disconnected the supply line and started the engine and it is blowing air.  So I know the compressor and the governor is working and I know that the airline is going into the air dryer. I've read the instructions and it doesn't say that something needs to be removed for air to go through the dryer. Am I missing something?

disconnecting the line and checking for air output is the simplest way to diagnose. Sometimes those airlines take a convuluted path, confusing their origin.

[Jcparmley]

Ok. I was wrong. The air is pumping. It is going through the dryer. It is filling the first tank between the axles. However, it is not filling the other tank nor any of the air bags. Air gauge is not reading air build up. Brake pedal still on floor.

[buswarrior]

All of that is normal, for no air beyond the wet tank.

How much air in the wet tank? A whimper or a hurricane?

At no pressure, a large air leak doesn't make very much noise. Easily overwhelmed by engine noise.

The entire air system staying empty beyond the wet tank, would be a strange thing indeed.

Happy coaching!
Buswarrior

[Jcparmley]

I drained the wet tank and a bunch of water came out.  The air is more than a whimper.  It was blowing quite hard.  Perhaps I should have let it run longer?  The other tank next to the wet tank didn't have any air pressure.  I looked all the way around the bus and didn't hear any leaks but like you said it could be hard to hear over the engine running.  What are my next steps?

All of that is normal, for no air beyond the wet tank.

How much air in the wet tank? A whimper or a hurricane?

At no pressure, a large air leak doesn't make very much noise. Easily overwhelmed by engine noise.

The entire air system staying empty beyond the wet tank, would be a strange thing indeed.

Happy coaching!
Buswarrior

[chessie4905]

consider a standalone compressor and 50 feet of air hose plumbed into coach with a quick connect. sit it where you cant hear it run while you check for leaks. good to have in future, saving running engine to build air and not planning to drive, and for campgrounds to air up before leaving. one like this or similar could be kept in coach for travels. just an example as like tires abnd oil, everyone will state their favorite.

https://www.harborfreight.com/6-gallon-175-psi-high-performance-hand-carry-jobsite-air-compressor-56829.html