Old fuel.

[Jim G]

Any suggestions on how to get the old fuel out of the tank?

I was able to get what was left in the sediment bowls to burn, took a fair bit of heat but it did burn. 

I only have about an inch left from when I stuck a siphon hose in. I don't want to remove the tank, I'm concerned if I remove (if I even could after 70some years) the drain plug I'd never get it to seal again.

I have thought of making an adapter with a lenght of garden hose and use a shop vac, or disconnect the fuel line from the fuel pump and use gentle air pressure (very gentle) and blow it out. 

Or, just dump a couple cans of seafoam in the tank, and top it with 5 gallons of fresh gas and hope for the best?

[Plymouthy Adams]

Personally, I would take the time to drop the tank and inspect it inside and out and flush it also.  I would back flow some solvent through the output plug back through the oilite stone filter for bit more cleaning effect....

[kencombs]

 Do NOT use the shop vac idea!!  yes, I yelled not.   The arcing of the brushes with gas vapor moving thru the machine is very dangerous.  Yes, it has been tried with terrible results.

 

I also vote for removal and thorough flush, cleaning and inspection.  I've seen too many acquaintances  go through that, over and over.  fuel filters, pumps, carbs etc and then finally pull it anyway because the fine stuff just keeps coming loose.

[Jim G]

11 minutes ago, kencombs said:

 Do NOT use the shop vac idea!!  yes, I yelled not.   The arcing of the brushes with gas vapor moving thru the machine is very dangerous.  Yes, it has been tried with terrible results.

 

 

Some times you need to yell to be heard. Honestly I never thought of the vapours . . . I had planned on having a fire extinguisher handy, but yes, you are right, that idea is NOT worth the risk.

[PT81PlymouthPickup]

I agree with everyone above. And, in my opinion most all of those additives are just a waste of money. If you really don't want to remove you tank, you might try removing that drain plug on the bottom of the tank. Often they'll come out easily. Use the right wrench and don't put too much force on it in case it's severely rusted in there.They're a tapered plug and should reseal fine especially if you put a little thread sealant on when reinstalling. If the last bit of old fuel isn't chock full of crud and particles of rust? Then just fill with fresh fuel. My truck had only a sediment bowl on the fuel pump. I installed a inline filter before the pump and all is well. Keep an eye on the sediment bowl. You might have to clean it a couple times until the lines are purged of whatever crud might have been in there. Like stated above, the surest way is to remove the tank and inspect. Sometimes these old tanks are UN-salvageable. They make brand new ones for my era truck 39-47, ($250) I'm not sure about your year? AND! Whatever you do when working around gasoline, make sure you have no sources of ignition. Just a light bulb in a drop light if broken could ruin your day or worse. 

[Jim G]

2 hours ago, PT81PlymouthPickup said:

. They make brand new ones for my era truck 39-47, ($250) I'm not sure about your year? AND! Whatever you do when working around gasoline, make sure you have no sources of ignition. Just a light bulb in a drop light if broken could ruin your day or worse. 

1949 Fargo,

And a good reminder on the trouble light, My Dad drilled it into me to not work on a gas tank with anything but a flashlight (yet I have no idea why that didn't occur to me about the shop vac . . .) One thing I love about the LEDs in a trouble light is they don't easily break . . . 

I might just try to gently see if the plug will come out of the bottom first.

[JBNeal]

I'd be hesitant to torque on that plug, I have seen damage around the drain from too much torque on a rusty plug then it's a headache to rectify that...if you've already siphoned out all but that last inch or so, then maybe adding fresh gasoline + additives is the way to go to dilute the contaminants and pass them through the carburetor...though for a truck that's been idle for an extended period, I'd prefer to turn that tank upside down to drain and drum on the bottom like Tito Puente to knock any debris loose, then rinse with diesel...

[Tooljunkie]

A neighbour lit up a shop vac,figured he could pull a few filings out of the fuel line after cutting it. 
before he realized what he had done the turbocharged gas fueled flame thrower really got his attention. Managed to get the walk through door open and threw it out into the snowbank. In the meantime the vacuum had started a siphon effect on the fuel line (3/8”) and the puddle was growing by leaps and bounds. 
he had to make sure there was nothing on fire before he started dealing with the spilled gas. A harrowing experience for him. Original owner ‘69 dart gts. Mint condition. 
 

 

i put a wrench on my rotten rusty 51 gas tank and plug came out easily. Was the only thing worth keeping from the tank. 

[Plymouthy Adams]

you could run to a harbor freight if near you and get a siphon tool that connects to your pressure air line and suck all the gun and junk out for the most part....but I still think it would be worth it to drop the tank and truly know what you are facing and have to work with.  

 

 

[Bluzhog53]

I tried to do it your way and it just did not work. It’s been a long time sitting and you constantly are chasing little crap through your fuel system and once it hits the carb, you really start cussing!!! I vote to drop the tank. It’s only 4 bolts and a couple lines. Turn it upside down and do the bongo on it. Toss some nuts, bolts, ball bearings in it and take it for a ride in the back of your other pick up for another week or two on some windy roads and rail road tracks and rattle that puppy! Rinse it out good with some solvent/diesel afterwards and try using a boroscope to see inside what you have left. If it’s good, get r sealed up and reinstall. Add good gas. I would also pop a couple in line fuel filters (clear) before the fuel pump to catch any crap that might be left and just toss em as needed. A bit more work but worth it in the long run. Bad  dirty fuel just keeps biting you And costing   You   Good luck!

[Plymouthy Adams]

I just dropped a fuel tank that feels as though it is about 1/3 full and it has been sitting literally over 3 decades...any bets/guess as to the contents.....possibility of finding Jimmy Hoffa..........??????  as an aside here, it took a strap wrench to break free the filler cap...

Edited August 17, 2020 by Plymouthy Adams

[ggdad1951]

Drop it, and unless the money is an issue take it an to a place that works on fuel tanks, have it inspected and sealed.  Tank Renu does a good job.

[Bluzhog53]

10 hours ago, ggdad1951 said:

Drop it, and unless the money is an issue take it an to a place that works on fuel tanks, have it inspected and sealed.  Tank Renu does a good job.

Pretty much what I did once I saw what I was dealing with inside... wasn’t with all the other hassle. Used an old guy in San Jose. Does radiators too. Dang near new now!

Edited August 17, 2020 by Bluzhog53
Add

[48Dodger]

 

Its an old Thread I did on the gas tank innards...sorry about the photobucket images...I don't pay them. But you get

idea of what's going on.

 

48D

 

ps The thread is back in the day when we didn't try to stay on topic.

[MBF]

I pulled the plug on mine before sealing it.  I think it was just a 1/2” drive ratchet w an extension.  I was surprised how easily it came out.  Use good judgement and finesse.  You may be surprised.

[50mech]

Fluid transfer pump

 

https://www.google.com/aclk?sa=l&ai=DChcSEwjnxPDv4ajrAhUXboYKHSNGC2wYABAEGgJ2dQ&ae=1&sig=AOD64_0u278MNVew7sdm0Z6qp9QhtfO30w&adurl=http://www.harborfreight.com/Multi-Use-Transfer-Pump-63144.html?ccdenc%3DeyJjb2RlIjoiNzQ4Njc3ODkiLCJza3UiOiI2MzE0NCIsImlzIjoiMy45OSIsInByb2R1Y3RfaWQi%0D%0AOiIxMTkzNiJ9%0D%0A%26cid%3Dpaid_google|||63144%26utm_source%3Dgoogle%26utm_medium%3Dcpc%26utm_campaign%3D%26utm_content%3D%26gclid%3DCjwKCAjwm_P5BRAhEiwAwRzSO91_XQSzmW3k87IOatdrhNY5qPhMJis9bkreAkP8uxeExLJlOMv0UxoCDNcQAvD_BwE&ctype=5&ved=2ahUKEwigquLv4ajrAhXNh1MKHRhKDywQwg96BAgBEE4

 

 

Electric fuel pump works too, without all the work, a bit more money though.

 

If you don't pull the tank, at least pull the filler neck, replace the joint that's probably now just a rag and some clamps, and clean out the neck....it's often the source of rust chunks that won't dissolve.  Everything else will for the most part. I've had much better luck with cam2 than additives.

Edited August 20, 2020 by 50mech

[greg g]

WARNING, WARNING, DANGER !  You have been schooled on flammability issues, the is about very small parts.  If you decide to drop the tank, there is a very small farrel  in the connection of the talk outlet and the fuel line. When released it will transport itself to the deepest, darkest point in your shop. Be aware of it's presence and corral and secure it before it can flee. Without it the line to tank connection will never seal leak tight.

Edited August 20, 2020 by greg g

[Merle Coggins]

The trucks don’t use that type of connection, Greg. At least my truck tank doesn’t. It’s just a standard female inverted flare connection port. 

[wallytoo]

1 hour ago, Merle Coggins said:

The trucks don’t use that type of connection, Greg. At least my truck tank doesn’t. It’s just a standard female inverted flare connection port. 

 

same for my b-1-fa