Bus Building pressure on gauge, But no air to system?

[eagle19952]

alright, I'll probably lose my guru card for asking this..
i know the ppv is the pressure protection valve.
what is the e-filter ?

[bevans6]

On an MCI of a certain vintage (mine is 1980) it's just an in-line air filter to keep contaminants out of the accessory and suspension air system.  It's on the output from the dry tank after the pressure protection valve.

[eagle19952]

On an MCI of a certain vintage (mine is 1980) it's just an in-line air filter to keep contaminants out of the accessory and suspension air system.  It's on the output from the dry tank after the pressure protection valve.

thanks, but why e- and not a- ?

just curious.

[buswarrior]

E type filter was a vendor descriptor.

Obsolete now

Happy coaching!
Buswarrior

[Jim Eh.]

Must have worked really well at -40°

[buswarrior]

The E filter is a long way into the system, the contaminants and moisture would normally be left behind by the time the air gets here.

They didn't cause any grief.

That's why they were/are mostly ignored.

happy coaching!
buswarrior

[chessie4905]

Mine has a small filter under dash with a type of horse hair in it. Filters air going to wiper motors. Occasionally, remove, disassemble, clean mesh in solvent, and reassemble.

[NewbeeMC9]

So is the PPV the one way/check valve after Dryer that can cause a problem? Or us there another valve?

[Jim Eh.]

The E filter is a long way into the system, the contaminants and moisture would normally be left behind by the time the air gets here.

They didn't cause any grief.

That's why they were/are mostly ignored.

happy coaching!
buswarrior

Since it is basically a "closed" system, would it not be suitable enough to filter the compressor inlet air properly and then even the compressor would have "clean" air to work with as well, as all the valves downstream, in the first place?

[buswarrior]

Most air compressors intake is plumbed from the engine air filter in our coaches. Some older or medium duty, or retrofitted, there should be a stand alone filter.

The compressor is a source of contaminants, but that normally drops out mostly in the wet tank, if an air dryer is absent. The air dryer normally captures contaminants. Through neglect, as each loads beyond capacity, the contaminants can get inhaled/pushed deeper into the system.

The PPV - pressure protection valve, via its spring internals, blocks air from filling less important parts of the system, until the brake tanks are up to the setting, then the air pushes past to fill the rest. They usually fail by letting air in before they should, not by obstructing the flo

It is safe to say that every air problem a busnut experiences is due to delayed parts replacement and neglect. Working through the air system in a methodical fashion to catch up the neglectof previous owners is a HUGE contribution to coach reliability.

And keeping the system properly dry, 365 days a year, winter freeze up won't happen.

Happy coaching!
Buswarrior

[NewbeeMC9]

Ok, got the bus shored up to my liking, got to the PPV, tooke the flarenut fitting​ loose, the other side is attached to that filter and is too close to the air tank to spin off, so back this afternoon too take the filter off and replace the valve, lol, so close....😉

Also the filter has a blowdown and is one of the cables by the passenger front tire, , not going to open it, thanks BW,

Keep ya posted...😎

[NewbeeMC9]

Okay, Update time, Got the PPV valve replaced, aired with compressor and fixed the leak that i didn't get tight enough, lol.  So aired up and Moved.  Also Changed the purge valve, It aired up and got to move the bus.  Thanks for all the help.

Now for another issue, not purging, will post a new thread...