What's the best way to drain the gas tank?

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PhotonFanatic

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I have the dual tank truck, (87 5.7L 2wd) and one of the fuel pumps died last year. Of course it croaked with a full tank of gas. I left it in there and didn't do anything about it, because I wasn't really in the mood to work on the truck at the time. But now it's time to drop the tank and fix the fuel pump, and all the bad gas has gotta go. What's the best way to get it outta there, before you drop the tank?

I tried a siphon hose but as I expected, there's a screen or something keeping gas thieves away. Found this but it's only for diesel I think:

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Ellie Niner

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I've been using a cheap inline electric fuel pump to do the dirty work for the last few years. I disconnect the fuel outlet as close to the tank as I can get, slip a hose over it, and usually power the pump off a 12v power supply or spare battery or whatever is expedient. It pumps ~1 gallon a minute or so, and it usually takes me about that long to round up gas cans and empty them... Surprisingly, the weenie fuel pump I have was able to pull fuel out of the tank on my 1962 Stude Lark from up in the engine compartment without manually priming it.
 

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I usually drop it full or not. Lol. But this screen doesn’t sound right? I have dropped a lot of tanks and have never seen a screen.
 

PhotonFanatic

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I've been using a cheap inline electric fuel pump to do the dirty work for the last few years. I disconnect the fuel outlet as close to the tank as I can get, slip a hose over it, and usually power the pump off a 12v power supply or spare battery or whatever is expedient. It pumps ~1 gallon a minute or so, and it usually takes me about that long to round up gas cans and empty them... Surprisingly, the weenie fuel pump I have was able to pull fuel out of the tank on my 1962 Stude Lark from up in the engine compartment without manually priming it.

Got a pic of the fuel pump? I'm imagining using a stock fuel pump apparatus so that the lines are easy to hook up
 

PhotonFanatic

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I usually drop it full or not. Lol. But this screen doesn’t sound right? I have dropped a lot of tanks and have never seen a screen.

Well it's an 87 model, I don't know if that matters. Maybe they started putting in some kind of thief block later on. Or maybe I'm doing it wrong and I just need to try harder. Have you guys used siphon hoses on the fuel filler neck successfully?
 

eskimomann209

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It is a good point. I have an 87 tank but the older fuel Neck.
I’d be tempted to remove the hose clamp from the rubber fuel neck in top of the tank. Lift t it off and slid the hose in through the top of the tank if your neck somehow has a screen in it.
 

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I was going to suggest burnouts, as the best way to drain the gas tank. As well as your wallet.

But in this case, the anti siphon feature is a problem. Can you tap in at the tank switch and try to draw the fuel through the in tank pump? Eskimoman has a great idea too. Let us know how you did. Maybe pictures too...
 

Ellie Niner

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Got a pic of the fuel pump? I'm imagining using a stock fuel pump apparatus so that the lines are easy to hook up
For some reason, my phone doesn't feel like sharing its photos right now (I think it's waiting for a software update to be installed with a claw hammer), but this is what I'm using:

Mr Gasket Micro 12s Fuel Pump

I just pulled it out of a junk box and rigged it up with about 3.5' of hose on the suction side and 18" on the outlet to drain the tank on an '89 Electra that munched its way through 3 or 4 Chiwanese in-tank pumps in the space of two years (it now has an external EFI pump), and I've used the thing for transferring gasoline in other places a handful of times. I guess it's only rated at 35GPH, so I that 1GPM estimate was a bit optimistic.
 

ChuckN

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Well it's an 87 model, I don't know if that matters. Maybe they started putting in some kind of thief block later on. Or maybe I'm doing it wrong and I just need to try harder. Have you guys used siphon hoses on the fuel filler neck successfully?
I tried emptying out my fuel tank this winter, same as you, I found it impossible to get a siphon hose in the tank. Mine is an ‘81, don’t know if it’s just a kink in the filler tube or what, but I couldn’t get it in there no matter how much I tried.
 

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No need for a 20.00 self priming hose. For anyone that needs to know if you take a hose submerge it in water,run a spigot into it what ever you need to do to fill it with water. Put your thumb over the end,just like a drinking straw as long as the one end is capped the liquid will stay in it. Put the siphon end in what you are siphoning, hold the end with your thumb below siphon level and remove your thumb,the water will start the siphon.
 

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I have dropped a lot of tanks and have never seen a screen.
I've never seen a screen either. I think you need to try harder with a smaller diameter hose. It is kind of a pain to get the hose down in position. I've had success siphoning with an old air compressor hose.
 

PhotonFanatic

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Pop the fill hose off at the tank in the wheel well and use on of these?

You mean you don't have to get gasoline in your mouth? Awesome!

Joking aside I usually just use a small clear hose like a straw and then stop when I see it flowing. It will do the job to get the gas moving. I just need a way to get the tube into the tank.
 

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