Is this suppose to leak?

[mikey72]

https://drive.google.com/open?id=14EGm6qDKDxdrv-e2xwfLWeDq7NEhPNui

Hey guys and gals, I'm baffled...not sure what this part is.  Any help is appreciated.  I looked through my digital parts manual and couldn't find it....it must be missing that page or something.

8v92

Got a water bottle with soap and started spraying after hearing a hissing.  Found this "switch" or whatever it is making bubbles. 
1. What is this switch device?
2.  I'm assuming it shouldn't be leaking air, correct? :-)
Thanks!!!!

[luvrbus]

That is your buffer switch for the Jakes some leak a little air but not much because yours is a combo fast idle Jake switch flip it on fast idle a few and it may stop,the switch it's self is not leaking it is the plunger from the fast idle cylinder

[mikey72]

 The "leak" does seem to quiet down once fast idle is engaged, thank you for the info!

[luvrbus]

The cylinder has o-ring inside that goes bad you pop the snap ring and pull the cover and piston comes out to replace the o-ring if you never worked on 1 it's best to have a qualified shop do it because that area your engine if not careful and know what you doing can run away