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81 Brat Fuel Pump Question


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I have a leaking fuel tank and decided to throw a tank in the back so I can drop the old tank and see if it can be repaired.

 

What I need to know, hopefully by later today if possible, if the intake and return fuel lines are the same size or different. I am using an old Toyota tank and it shows the lines being one size and I remember there being mention of two different size lines when removing the tank but I no longer have access to the manual that mentioned it.

 

Thank you

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I don't know about the Gen 1's specifically, but in the 80 to 84 body style, the supply is about 5/16" and the return is a bit smaller than 1/4" - probably about 5mm. I used 1/4" fuel injection line when I changed the rubber in the return line's over to high pressure - it's a bit large but works if you clamp it.

 

GD

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LOL. Out here in my neck of the woods it's a common thing to see farmers with tanks in th beds of their trucks, and there are a few pulling trucks that have the tank in the bed as well. That is what gave me the idea.

 

If I can fix the old tank, it will take just a few mins to switch everything over.

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Pull the fuel tank vapor line (the rubber part) loose from the firewall and leave it open. Find the line that hooks to the carb float bowl - leave that open. Cap all the other's and you're done. The tank and carb bowl need the vapor lines open to the atmosphere to prevent pressure from forming due to evaporating gasoline. The other lines are just there to facilitate the purging of the canistor and will not be used if you aren't useing the canistor.

 

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There are three lines comming from the tank - fuel supply, fuel return, and a vapor line. So whichever isn't hooked to the liquid gasoline lines is pretty much the one you want.

 

On the carb there should be an electric solenoid on carb itself that opens/closes the vapor line from the float bowl. Look for that and you should find the rubber line to connects from the carb to the hard-line's under the manifold - being an older 1600 it may not have the solenoid, but look for a line comming off near the bowl. Trace the hard line to the vapor canistor connection point and just don't cap whichever one it turns out to be. Cap the rest of the hard lines (a bit of the old tubing with a bolt threaded in the end works just fine) and you are done.

 

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I hooked the smaller line (#4) to the matching sized line.

 

She started with no gas leaks.

 

The 3rd line with the large section intakes air. Unplugged it makes the engine run rough. Plugged it runs better. I plugged it for a bit and it idled like before but it would choke when reved and quite often would drop rpm til it almost stopped unless I gave it gas.

 

The second line does nothing plugged or unplugged, so I kept it unplugged.

 

24049_1381835061973_1114842834_31157120_8287976_n.jpg

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Pull the fuel tank vapor line (the rubber part) loose from the firewall and leave it open. Find the line that hooks to the carb float bowl - leave that open. Cap all the other's and you're done. The tank and carb bowl need the vapor lines open to the atmosphere to prevent pressure from forming due to evaporating gasoline. The other lines are just there to facilitate the purging of the canistor and will not be used if you aren't useing the canistor.

 

GD

 

Will the vapor line drain fuel when it's unplugged?

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