Need Help with Air Leak

[Alan-MCI5A]

Our bus has been sitting awhile and when I started it, I heard a leak just behind the front wheels.  I have attached a picture showing the component that is leaking.  The leak is coming from the smaller unit in front.  It is on the passenger side and is located next to the air tank.  It has a plastic cap and stopped leaking after I gave it a tap and got its attention.  Thanks for the help....Alan

[captain ron]

You might want to try and shrink the picture down.... i had to put my laptop at one end of my bus and walk to the other end to see it clearly

[Alan-MCI5A]

Thanks Captain Ron....This is my first post and I am trying to figure things  out.

[buswarrior]

Hello Alan.

That looks like a pressure protection valve, mounted in front of the larger filter, on my MC8 called a type "E" filter.

If it is, it will maintain a set pressure behind it, and only allow air above that pressure to flow deeper into the system. The filter is there to trap whatever is roaming down the airlines. Note the valve on the bottom. Notoriously under maintained by many fleets.

Neither should be allowing any external escape of air. Supposed to be sealed.

The pressure protection valve is used to prevent a blown supply hose to some auxiliary, like the windshield wipers, from dumping all the brake air. Depends on the vintage of your coach as to exactly what is and what isn't protected.

happy coaching!
buswarrior

You buy them generic, and have to set the pressure by winding the cap up or down. Easier to set before install, and tighten the locknut.

[Alan-MCI5A]

Thank you buswarrior!

Is the entire unit the pressure protection valve, or just the smaller unit?  I will check with ABC on a replacement...until then, I will carry my trusty hammer to keep it in line. 

Alan

[buswarrior]

The little one in the front of the picture is the pressure protection valve.

It should not leak externally, I'd not be trusting that it won't simply break apart and leave you stranded with one of those strikes with a hammer.

Be sure to not strike the cap, strike the cast body gently to get whatever stuck bits to move to whatever position they are to get air integrity.

happy coaching!
buswarrior

[Alan-MCI5A]

Thanks again buswarrior.  I did find it in my manual, which says it can be disasembled and cleaned.  I will call ABC in the morning and see if they have one. 

Alan