Gas Tank question

[tscott9330]

Ok, on the 78 gas tank, there are 4 holes. 3 are in the metal collar where the cap screws into. The larger of the 3 is a feed line to the pump, the smaller is a return, and the third is a vent. There is another in the tank itself, but does not go all the way into the tank. It does not go through the plastic liner of the tank. Origionally there was a fitting of some type screwed in there, but I have misplaced that at some point.... Go figure, I lost a part. What does this 1/2 inch threaded hole do?


Tom

 

[74bigblock]

Wish I could help you out... the '78 tank sounds mighty different from the '74. Mine has the sending unit on the bottom with an exit for the fuel. On the drivers side there is a return line, and a vent line going to a junction/overflow box that feeds to the charcoal canister up in the drivers front fender. The only other hole is the filler neck.


Hope this helps a little.

Dave

 

[Tom73]

Is that to allow air into and out of the space between the bladder and the tank so that the bladder will shrink as the fuel load goes down and expand when gas is added?

Just a guess....

tom...

 

[tscott9330]

well, Thats what the vent is for. It equalizes the preasure in the tank. The plastic liner is very stiff, It would take a severe preasure differential to collapse it.

 

[tscott9330]

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