Re: Gas tank selector

[Eric Hegstrom <ehegstrom@domain.elided>]

Well the O-rings appear to work O.K. I will forward the size tomorrow
(if I remember). I spoke with some of the mechanical engineers I work
with and they warned me that Buna-N is not the optimal choice for
gasoline. They believe it will break down faster. They suggested
Bitron-A as the best material. Nitrile is a second choice. Any
fluorocarbon (Teflon) or Fluorosilicon formulation should do the trick. 

I picked mine up at the Ace hardware and they guessed they are probably
Buna-N. I was told that Buna-N would tend to swell slightly in gasoline
which would be bad in a dynamic application but I think in our case it
wouldn't be a problem.

I will pull the cover in a year or so and see what they look like. I
highly suggest replacing them because it is the easiest repair job I
have ever done (a screwdriver and a half hour including the drive to the
Ace Hardware and 20 minutes sorting through the 100's of o-rings they
stock). 

The cover has a gasket. My guess is you'll never find one anywhere. You
could cut your own; I remember my Mom telling me stories of cutting a
water pump gasket out of a telephone book cover for my dad when they
were broke newlyweds. Anyway, I just threw some Permatex Form-A-Gasket
(2b non-hardening) on there. I guess you would want to make sure you
have a good seal because any leaks may not be readily apparent ( my
guess is that since it is under negative pressure you would just suck
air into the gas line instead of seeing any visible fuel leakage ).

Wow, it's taken me longer to write this email than to do the actual job
;)

All I can say is, "go for it!"

peace,
Eric

Chris and Ranae Procyk wrote:
> 
> Good job!!-- procrastination again saves me.  McMaster Carr carries a
> zillion O-rings of different formulations.  Although they have a table in
> the front, I couldn't specifically find gasoline.. but I bet one of the list
> members can tell you what material you want (Buna-N, etc).
> 
> So does the case itself have any other gasketing that might need replaced?
> 
> In Use: 70 1210 4x4 TE, 73 1210 WM
> Project (2nd time) 67 1000B PU
> Parts: 67 1000B TA   68 1100 4x4 TA  72 1010 TA

-- 
Eric Hegstrom                                   tele: 520-617-0072 x402
Sonoran Scanners, Inc.             email: ehegstrom@domain.elided