Fuel line replacement - part 2

[Radek]

Hello again.

Thanks Stephane for your post.  I suppose you're right.  Once I'm there I
might as well replace the whole length.

Now the fun stuff.  Last night after work I got under the car and cut the
leaking line just to get the job started.  Gas started gushing out and would
not stop until I plugged it with a pencil.  I'm working on the return line
so I expected some sort of check valve to be in place to prevent fuel from
going the wrong way.  Nope!  Is there a trick I can use to prevent the whole
*#$% tank from emptying itself on my head?

Also, the existing fuel line is about 9 mm in diameter.  The brake line I
got from the parts place is thicker, 3/8" and probably will not fit in the
rubber hose it's supposed to connect to.  Should I go to the dealer to get a
metric fuel line?  What are the standard sizes of fuel lines, anybody know?

Thanks.
Radek
88 90Q