Hi Steve,
If the hose fits, you can wear it. It's a good idea to use a clamp on
it, just for extra security. Getting the right hose is best, but your
driveway repair will work until the proper hose arrives.
But that you have pressure shows another thing that needs attention.
On the firewall over passenger's legs is a black plastic cannister,
perhaps two in your car. It has three taps on the top, one goes to carbs
for vapor collection, one goes back to fuel tank, and one goes to rocker
cover. The pressurisation of the tank is happening because the line that
goes to the vapor separation cannister, that round silver metal thing in
the right rear corner of the boot, is plugged.
The idea is that air can enter the black cannister, the Adsorbtion
cannister, through the bottom. When the engine is running, its vacuum
pulls in gas-tank vapors that the adsorbtion cannister has collected and
can also pull in clean filtered air for crankcase venting.
Also happening is that the gas in the tank is making vapors that can't
vent because the cap is "unvented" so they pass forward through the
separation cannister and onward to the adsorbtion cannister where they
are captured by the charcoal medium. The vapors don't get into the
atmosphere, and the engine gets to burn whatever vapors can be sucked
into the intake manifold.
When you have pressurisation in the adsorbtion cannister, the vent line
from adsorbtion cannister to separator is plugged with sludge from years
of vapors. Disconnect the line at the separator and push on a rubber
hose that will extend out of the boot. Tape that to something so it won't
spatter sludge when you blow compressed air into the metal line at the
adsorbtion cannister end. You may find that you can't blow through the
line at all. Introduce some carb cleaner, let it work, and keep trying
until it blows a nasty gob of stuff out the rubber hose.
Meantime, disassemble the charcoal cannister. Make a new filter for the
bottom out of a piece of scotchbrite and refill charcoal with fishtank
charcoal. Walmart is a good source for these exotic items. Reassemble,
and the pressurisation problem will be solved.
Bob
On Fri, 28 Jul 2006 00:38:57 -0400 "Steve Shoyer" <Steve@shoyer.com>
writes:
> Does anyone know the correct specs for the fuel line between the tank
> and the fuel pump? The line on my 1980 MGB split today right at the
> fuel pump connection. The car died at one point on a twisty road -
> I pulled to the side, smelled gas and saw drops on the road, but
> couldn't see anything wrong under the hoos. I tried restarting the car
and
> it worked fine, so I continues on my way. When I got back home, I
> noticed drops on the driveway, and the gas smell was back. Gas was
pouring
> out of the slit in the line - it was ahot day, so the fuel in the tank
> must have gotten pressurized. Removing the gas cap stopped the gas
leak.
>
> Anyway, I replaced the line with some 5/16" line I had in the
> garage, but I wanted to make sure that's the right size. There was
also
> nothing clamping the hose to the pump - it's got a small barb there,
but I
> didn't know if it should have a hose clamp there too.
>
> Thanks.
>
> --Steve (1980 MGB)
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