My annoying question #5,763 (Yes, I'm counting) Aux air connection

[Paladin]

Bus = '75 MC8

Precisely where does one tie in to provide extra air to air up via an external compressor without running the engine or get air from in order to air up outside things like my date for next Friday?

Does it need to come off of the on board compressor or can it be obtained elsewhere? As I said, I need to know precisely or I will be pulling left front headlight looking for air. Photos always help. Also, what parts need to be picked up in advance of starting the job?

Disclaimer: I'm only half as inept as I make myself out to be but I really am not the most familiar with my engine workings like the compressor and the various lines yet.

[bevans6]

I use two different points on my MC-5C.  To add air, I use a connection I added at the ping tank in the engine bay.  That sends the air in to the air dryer and the wet tank.  You need to adjust the air pressure so that it is lower than the cut-out pressure, or the governor will cut out and send your compressor air out the air dryer vent.  It's also important to start adding air when the pressure is below the cut-in pressure, or again the air will vent out.  The advantage is that you are adding air through the air dryer, and before the pressure protection valve.  If you add air after the pressure protection valve it can (is supposed to, actually) keep the air from passing back into the dry tank.  To take air out I added a connection to the auxiliary tank under the driver. 

Brian

[PCC]

Many of the vehicles have an air connection for a tow truck to apply air in order to move the vehicle.

That is where I connected my main auxiliary air source.

I also made a connection to the tank that provides air to the doors and front end suspension. I use the latter of those two more often, in order to keep those things aired up, but can switch to the tow air to build up the entire system to move out more quickly in the early morning hours.

[buswarrior]

What do you want to fill?

As noted already, in the curb side engine room access door, the "Drain Daily" fitting is a good candidate.

At the front, direct into the wet tank is also lovely, maintain the drain somehow, so you can dump the moisture.

The emergency fill under the driver just does some brake tanks, it's too late to remember which one...

It is your coach, and you may attach the aux air supply as you see fit, where it works for you, to fill what it is you need filled.

happy coaching!
buswarrior

[bevans6]

On our MCI's, the emergency fill just goes to the emergency tank.  Depending on the status of the check valves that isolate the emergency tank from the rest of the system, it may or may not fill the auxiliary tank, or find it's way past the PPV to the dry tank - if all is working as designed, it will isolate the emergency tank.

Brian

[buswarrior]

Yup, that's it exactly.

Paladin, what do you want to accomplish with this exercise?

happy coaching!
buswarrior

[FloridaCliff]

Dave,

You are a pain.... ...Just kidding!

I tapped into just before the ping tank with a tee.  The existing lines just feed through the top of the tee.

I put a 1/4 turn shut off valve on the bottom and then an air connection.  I use this to hook up my home compressor when testing for leaks.

Its around the back of my shop, so very quiet.  This is also were I hook up the spare emergency compressor in the back bay with a short hose if needed.

Make your plan and take a phone camera shot to the local hardware, so they will know what you are trying to do, and collect parts.

Best of luck,

Cliff