I don’t know why the
method of finding leaks in fuel tanks should not work for
the seal. But read
this and it might give you an idea of how to find the leak
without smoke, water
– anything other than a non-volatile gas.
Realize this hasn’t
been tested on a seal so it may be only a “good thought”
of getting
it done.
Use of a
Freon sniffer.
Purge the
seal. Flush the inside of the seal with Freon,
pressurize it a tiny bit just to
have excess Freon in the line, seal it (reconnect it to
the pump line), then
use a “sniffer” to detect the very smallest micro leak.
OK, so
there are not two ends of the seal – that is you can
only flow gas into
the seal but not through the seal. Now, you’ll have to
use some ingenuity
in getting the Freon into all of the seal. Vacuum?
Flow
plenty of air over all areas for a while to remove
residual Freon pockets after
putting Freon in the seal and before your search begins.
Now if you find a leak
using a sniffer, you might have an air leak there too.
Just make sure
there’s positive pressure (tiny amount) in the seal when
searching for
that micro amount of Freon. If you close the door and
then pressure up the seal
with Freon, use the sniffer around everything to find
the leak.
CAUTION: Freon is not a life supporting gas.
Don’t make the
mistake of filling the pressurized cockpit with a gas
that doesn’t
support life. Test the sniffer with a small amount of
Freon first to make sure
it makes plenty of noise in the presence of Freon. Then
if the sniffer is
making noise all the time, get out and start again by
purging everything with
air. The sniffer I used is sensitive enough that purging
takes a while to get
rid of all residual Freon. I didn’t have a pressurized
cockpit to deal
with so this may not be an ideal method. But it works
for finding leaks in
tanks.