I have tried several fixes . adding a inner hose to help bleed air from tank. Now thinking about adding a vent valve to the fuel sending unit. what is happening , after a very short time filling the tanks the fill tube chokes off due to an air bubble . It does not drain very fast. I have checked for pinched fuel line . Any suggestions that will solve this problem/
thanks Sim

 

There is a white plastic vent in the middle top of the tank, it or its hose could be clogged.

 

Is this also the roll over valve? and I do need to remove the bed to get to it?
Thanks Rod

 

I just changed the rear tank in my 84 dsl, and inspected mine. It appears to allow air to flow in both directions, but will close if splashed with liquid fuel. On a car, it is plumbed to the charcoal canister, but diesels are charcoal exempt, so it is just capped and clipped to the frame near the sender. I would just inspect that plastic hat, and blow air into the hose to see if it flows. You may be able to access the front one with difficulty, but for the rear the tank will have to drop, or box raise.

 

ok newt week I left bed and check
thanks