[DeTomaso] Vent to tank gas leak

[mikeldrew at aol.com]

Bud wrote:
 
I have had a gas leak at the factory gas tank vent and thought it was 
due to
poor tension at rivets or bad gasket. SO I removed rivets, taped holes 
for 10/32
machine screws and inspected what looks to be a good gasket. 
Reinstalled and now
I still can't seem to find a way to get it to not leak--------appears 
to be
leaking around threads. Is there a better than stock gasket that would 
solve my
problem? Thanks for any thoughts you may share.

>>>I had the same problem; it drove me nuts.  Part of the problem lies 
 from the fact that the tank vent is not exactly at the top of the tank; 
when you fill the tank it's partially submerged.  The guy who put my 
car together made the mistake of using RTV to 'seal' it, not realizing 
that RTV dissolves in gasoline.  So among other things I spent years 
plucking RTV out of my clogged fuel filters, and being very embarrassed 
every time I filled the tank, as my cue to stop pumping was when a 
gallon of gas poured out the bottom of the car all over my shoes.

To seal this thing properly, I got turned on to a product called 
Hylomar.  It's an RTV-like substance, comes in a small (somewhat 
expensive, i.e. $21 for 3 ounces) tube, and is totally impervious to 
fuel.  It's used in place of gaskets by several of the OEMs.  It's blue.

At the time I bought mine, it was rather difficult to find.  Doing a 
Google search, I now find that Permatex has started distributing it 
under its own label, in smaller quantites, and cheaper.  Here you go:

http://www.amazon.com/Permatex-85249-Hylomar-Universal-Dressing/dp/B0018PSATY

You may be able to order this stuff through your local parts store and 
save shipping charges etc.  They probably don't carry it in stock, but 
if they carry Permatex items generally, they can get you a tube if you 
provide the part number for it.

Use this stuff liberally (including around the threads) and your gas 
tank filler neck and vent leaks are over.

BTW if you haven't taken the time to replace your gas tank vent with 
one that incorporates a check valve, now is the time.  This is a 
simple, good safety modification that isn't very expensive.  I got mine 
 from Precision Proformance; it cost $35.  It's actually a standard 
(cheap) Ford part with a custom adapter to enable it to be used on the 
Pantera tank.

Mike