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Cadillac & LaSalle Club Forums => Technical / Authenticity => Topic started by: Daffer on March 30, 2025, 06:25:30 PM

Title: need to drain gas tank, how do i drain it when plug is frozen?
Post by: Daffer on March 30, 2025, 06:25:30 PM
I need to drain my gas tank on my 1950 cadillac, im having trouble since the plug is frozen and i didnt expect that, my mistake. i tryed siphoning the gas but the tub wont go past a certain point. so im at aloss. I want to keep trying at the plug but im worried I may end up warping or doing damage to the tank when removing it and id hate screw anything up. any suggestions? -Joshua
Title: Re: need to drain gas tank, how do i drain it when plug is frozen?
Post by: The Tassie Devil(le) on March 30, 2025, 06:41:31 PM
The easiest way would be to remove the pipe from the inlet to the fuel pump and make an extender that goes into an external pump, and then pump the fuel into a couple of Jerry Cans.

This way you will get most of the contents out.

BUT, in the manner of safety, put a long outlet from the pump to the cans so there can be no chance of an explosion.

Any electric auto fuel pump will do.   I use an old Holley pump myself.

Bruce. >:D
Title: Re: need to drain gas tank, how do i drain it when plug is frozen?
Post by: Daffer on March 30, 2025, 10:10:03 PM
Quote from: The Tassie Devil(le) on March 30, 2025, 06:41:31 PMThe easiest way would be to remove the pipe from the inlet to the fuel pump and make an extender that goes into an external pump, and then pump the fuel into a couple of Jerry Cans.

This way you will get most of the contents out.

BUT, in the manner of safety, put a long outlet from the pump to the cans so there can be no chance of an explosion.

Any electric auto fuel pump will do.   I use an old Holley pump myself.

Bruce. >:D
OK I may give that a try. I'm just asking is trying the drain plug again a bad idea?
Title: Re: need to drain gas tank, how do i drain it when plug is frozen?
Post by: Big Fins on March 31, 2025, 04:16:38 AM
Spray it with PB Blaster a couple of times a day for a few days. That should break it loose.

Whatever bean counter did away with drain plugs in both transmissions and fuel tanks should be keel hauled very slowly in salt water.
Title: Re: need to drain gas tank, how do i drain it when plug is frozen?
Post by: _Cap_ on March 31, 2025, 08:11:16 AM
a trick i learned from my father is to take off the fuel line from the tank and put it in a bucket, then use a nozzle extension on for an air compressor and use a towel to seal it against the where you put in the fuel. When you put pressure in the tank it forces the fuel out.
Its a slow prosses but in a pinch it works pretty well
Title: Re: need to drain gas tank, how do i drain it when plug is frozen?
Post by: Daffer on March 31, 2025, 08:33:44 AM
Ill be giving the PB bladter a try today hopefully it works, if it don't I'll be trying the air compression method. I'll update you on how it goes. Thank you
Title: Re: need to drain gas tank, how do i drain it when plug is frozen?
Post by: Daffer on April 01, 2025, 07:16:49 PM
wanted to give an update sadly the PB blaster did NOT work, the plug is to stuck and i don't want to screw up a perfectly good tank by using a breaker bar. I took the suggestion of removing the fuel line from the tank only instead of using compressed air I held a siphon hose in were the fuel line would screw in and had my dad use the siphon to suck out the gas from the tank into a 5 gallon bucket. worked great now I can add fresh gas once im ready. Thanks
Title: Re: need to drain gas tank, how do i drain it when plug is frozen?
Post by: The Tassie Devil(le) on April 01, 2025, 07:41:49 PM
Congratulations.

Bruce. >:D
Title: Re: need to drain gas tank, how do i drain it when plug is frozen?
Post by: TJ Hopland on April 01, 2025, 10:26:02 PM
How did the gas look?  If the plug wasn't rusted on the outside you have to wonder if there is or was water in the tank and its rusted from the inside?
Title: Re: need to drain gas tank, how do i drain it when plug is frozen?
Post by: Daffer on April 03, 2025, 09:42:14 PM
Quote from: TJ Hopland on April 01, 2025, 10:26:02 PMHow did the gas look?  If the plug wasn't rusted on the outside you have to wonder if there is or was water in the tank and its rusted from the inside?

The gas was fine actually only like a year old, I only wanted to drain it since i rebuilt the engine I've chosen to start using non-ethenal fuel as not to gum stuff up. I'd assume the inside is fine, it looks like the dude I bought the car from did some light work to the fuel  system and replace the main fuel line and the little rubber connector between the gas tank and vent pipe.