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69 fuel tank pressure relief

1544 Views 9 Replies 9 Participants Last post by  SSsedan
My 69 fuel tank has two tubes from the back passenger side with two fuel line hoses about 4 inches long going to a wad of plastic that I understand was once some kind of pressure relief valve. I have not been able to find a replacement for such a valve. Should I plug these lines and if so what is recommended.
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For what it's worth;
I couldn't find the plastic vent thingy for my 69 either so I plugged the lines. Now if I drive on the highway for a long distance, there seems to be pressure build up in the tank. I tried a vented cap but the gas sloshed out on take off so I put the original cap back on. Been driving it that way for quite a while now and it seems to do OK but I probably have only put about 20,000 miles or so on it in 12 years and probably not too much of that was on long hauls.

Dean Call
A.C.E.S. # 00235
N.C.O.A. # 4350

[This message has been edited by Dean (edited 04-13-99).]
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Dean, I think those 2 short hoses are the vents. I don't have anything on the end of those hoses on my '69 and there hasn't been a problem (with non-vented cap). von
I looked for the pressure relief valve for my 69 also and could not get one. I simply have the two short hoses with some electrical tape wrapped at the open end to prevent dirt or water from getting in.
Actually, that plastic "thingy" is a liquid/vapor separator designed to keep liquid in and let vapor out. Most guys just leave it off. My preference is to find a good used part. I know of no source for a repro part.

Fred Aldrich
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Leave these two lins and the plastic thingy it is a vent and prevents the fuel tank from getting pressurized or from a vacuum which would starve the engine of fuel. The plastic vent probably just need some new filter material in it (they do not normally need to be replaced). I bought a crankcase filter that goes inside of the stock air filter assembly and used the filter material from it . I trimmed a small piece and stuffed it into the plastic tank vent because the old filter material was black and deteriorated.
for what it's worth, a chevy 4x4 has a breather/vent in a hose that goes up near the headlight on my 90 K-blazer. It is there to allow for wading a stream and it might work. Just a thought.
Vented gas cap: Can someone give me a part number for a vented cap for my 69 SS/396 El Camino. Stant,??????????
leave them open --- they are for ventilation and allows vapor to escape
i've had problems with fuel spilling out my vent tubs when my tank is full.( usually dosen't last long.) if you want to get rid of your plastic thingy ill gladly take it off your hands.

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