1984 with dual tanks leaks under pressure

[buddy84GMC]

I have an '84 GMC Sierra with dual tanks.  When I use the right tank it leaks when its under pressure after I turn it off for about a minute or 2.  A good bit as well.  The tanks also leak when I fill them but I think its just them being overfilled since nozzles do not even stay in the neck without being held in place.  Different shape I guess but will not stop leaking till it comes down below full tank.  What could be the issue here?  Thanks a lot.  This is scary when people smoke around the truck in the morning at work.  It leaks on stone and dirt so no one can see it! 

[gbskunk2006]

Try to narrow down the source of the leak first.  The fact that you mention "pressure" lends me to believe it might be as simple a worn out gas line hose or loose clamp.

If it is a leak in your tank, you're only real option would be to drop the tank(s) after draining, then either use some patching solution or replace it with a new one.  Once the tank is dropped however, you should also check the sending units as well since that might be the source of the problem.

Luckily, when I dropped my tank I already had the truck bed removed so the job of doing so was (I'm assuming) a lot easier.

Good Luck!

[choptop]

I dont believe it issupposed to be under pressure. Sounds like either a leaking filler hose, or sending unit gasket.

[VileZambonie]

Get a safe light and get under there. You just have to physically look. It shouldn't leak when you fill it either.

[buddy84GMC]

its definetely not the tanks actually leaking so its a line, hose, sending unit, or the actual cluster of part that switches the tanks.  When they are full it leaks only from the passenger side even if I fill the driver's tank from the whole set up that switches the tanks.  Not sure what that whole assembly is called but thats where its leaking from each time.  Thank for the pointers I will check it out.  The truck is actually in the shop right now so I will see if the bed is off and thats a good time to take care of this. 

[78 Chevyrado]

While the bed is off change every rubber fuel line whether it needs it or not, since you dang near cant get to them when the beds on there.   I did that when they had my bed off for paint, I showed up with tools and stuff and was done in 5 or 6 minutes.

[buddy84GMC]

While the bed is off change every rubber fuel line whether it needs it or not, since you dang near cant get to them when the beds on there.   I did that when they had my bed off for paint, I showed up with tools and stuff and was done in 5 or 6 minutes.

Thats a good idea.  That about the only rubber that was not replaced on the truck and it looked real bad.  I never needed to use that right tank since I only drove it once a week.  I will just start there.  Still not sure why it leaks when I let the pump automatically turn off but I will tackle that later.  I just never fill it unless I am driving more than 30 minutes to use that little bit up then its safe.  Thanks again