A couple of points. First fuel can leak out with the valves working
properly, the check valves only seal to about 0.2PSI. They have to be able
to pass fuel out the vent to allow for expansion of the fuel as it heats in
the sun. If the valve doesn't seal at all then you will get more leakage.
I have similiar valves on my airplane and if they leak, I get fuel on the
underside of the wing after landing.

Mike
MU-2


"Eric Brown" wrote in message
news:m1Pcb.24110$Ms2.5153@fed1read03...
I've owned a C210 for about a year now and have noticed that my fuel
vents,
and primarily the left one, seem to be leaking a larger amount of fuel at
full tanks than previously. A more experienced C210 owner told me that
each
of the wing tip vents has a check valve between the vent outlet and the
tank
to prevent fuel leaking through the vent. Sure 'nough, the POH shows one
check valve per vent on the fuel system schematic. The other owner also
said that he removed and cleaned his vents (I guess they get gummed up and
don't seal all the way) and that his leaks were gone. This was about a
month ago and I haven't seem him hanging around the airport or I'd ask him
how he cleaned them. Anyway, I asked my mechanic about this and he told
me
that the leaks were normal and that "they all do that" and there's nothing
that can be done.

So I have a former C210 owner telling me one thing and a mechanic telling
me
the complete opposite. Does anyone in this newsgroup have any experience
w/
C210 fuel vents that may be of some help? What I'm wondering is if this
de-gumming job can be performed by your's truly, since my mechanic doesn't
seem to think it's a problem. I could always just not fill the tanks to
capacity, but I'd prefer much more that if there's a component of my fuel
system that not working like it should, that it somehow be fixed.

Thanks in advance!

Eric Brown, PP-ASEL-IA (out of FFZ)