What is this?! Part of my compressed air system on 1983 35FC

[timvasqz]

notice the vent on the blue cap. if the vent clogs you get leaks in
the return and cavitation and starving on the extending. Not easy to
clog because the 3 grand worth to psi will suck the screen into the
reservoir then screw the pump on extend or blow the screen out and
suck dust at the next extend.
Greg ofTim&Greg

--- In WanderlodgeForum@yahoogroups.com, "compmanben"
wrote:
>
> Hi Folks,
>
> I have recently replaced by Bendix AR-2 air dryer. While I was
> working under the coach, I couldn't help but notice a part with an
oil
> leak. I'd like to do some work on it, but I don't know what it
is!
>
> It looks like it is part of my compressed air system. The lines go
> out of sight and I can't easily trace them.
>
>
http://groups.yahoo.com/group/Wanderlodg.../725524050
/pic/list
>
> I posted the pictures to a new "What is it?" album.
>
> Thanks in advance for your help!
>
> Nate Owens
> 1983 35FC
> "It's a Wanderful Life"
>