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-   -   Gas Tank Cleaning and Help (https://www.rx7club.com/1st-generation-specific-1979-1985-18/gas-tank-cleaning-help-1165615/)

OilyRotor16 03-19-24 09:14 PM

Gas Tank Cleaning and Help
 
Hey everyone, I dropped the gas tank on my ‘79 a few days ago, pumped the old fuel out of the lines, and finished cleaning the outside up, and was wondering what I should do about cleaning the inside. I realize I could go and get some evapo-rust and all that, but given that I’m sure a lot of newer cars still have rust in the tanks and a certain amount of debris, I was wondering if I could get by with just trying my best to rinse out the debris in my tank and just install a new fuel filter lol.


https://cimg7.ibsrv.net/gimg/www.rx7...fab7b6441.jpeg
This is through that fuel level sensor port
https://cimg8.ibsrv.net/gimg/www.rx7...8cbd40d87.jpeg
Same thing, but full view of how dang cleannn the inside of this tank is! :D I’m so pleased
https://cimg9.ibsrv.net/gimg/www.rx7...7f8611eee.jpeg
This is that side port for, I assume, extra fuel to pour into; it connects to the smaller rubber hose from the filler neck. This is the main issue that I’m concerned about
https://cimg0.ibsrv.net/gimg/www.rx7...9db81c324.jpeg
It’s so cleannn

Let me know what you guys think.

Thanks,
Pascal

KansasCityREPU 03-20-24 11:11 AM

That tank is in really good shape. I would not touch the inside of the tank itself.

That small stub pipe next to the filler is a vent pipe. A hose goes over that. I'd use a small longish wire wheel on a drill or dremel type tool and clean that out and treat with rust convertor. You could also tilt the tank up so that points down, plug it, and use some evap-o-rust and then treat with rust convertor.

LongDuck 03-20-24 01:19 PM

The tank is fine with a swish and drain, but that filler neck is washing fresh rust and debris down into your tank every time you get gas. It needs to be replaced with a rustfree part from another car, or bead blasted and coated. That rust is really bad, and may signal pinhole leaks, as well. I'd replace it, but thats me.

OilyRotor16 03-20-24 07:29 PM


Originally Posted by KansasCityREPU (Post 12596802)
That tank is in really good shape. I would not touch the inside of the tank itself.

That small stub pipe next to the filler is a vent pipe. A hose goes over that. I'd use a small longish wire wheel on a drill or dremel type tool and clean that out and treat with rust convertor. You could also tilt the tank up so that points down, plug it, and use some evap-o-rust and then treat with rust convertor.

Alright, will do.
When you mention plugging the vent pipe, do I plug it from the outside, fill the gas tank with evap-o-rust, tilt the tank so it flows into that pipe, and then let it sit?
Then I figured I would use some rust-oleum rust reformer to finish the treatment.
Thanks for the help :)

OilyRotor16 03-20-24 07:34 PM


Originally Posted by LongDuck (Post 12596827)
The tank is fine with a swish and drain, but that filler neck is washing fresh rust and debris down into your tank every time you get gas. It needs to be replaced with a rustfree part from another car, or bead blasted and coated. That rust is really bad, and may signal pinhole leaks, as well. I'd replace it, but thats me.

Thanks for the feedback, and if I were to replace the pipe, I assume I'd be cutting out that part of the tank and welding in the new one?
I'm not sure what it looks like in that side of the gas tank, as there's that metal partition separating them. I do have a parts car, but it's the rustier of my two cars, so I'm not sure if I could even get a spare pipe from there 😅

KansasCityREPU 03-20-24 08:34 PM


Originally Posted by OilyRotor16 (Post 12596859)
Alright, will do.
When you mention plugging the vent pipe, do I plug it from the outside, fill the gas tank with evap-o-rust, tilt the tank so it flows into that pipe, and then let it sit?
Then I figured I would use some rust-oleum rust reformer to finish the treatment.
Thanks for the help :)

I'm guessing this is the small tube and not the filler neck.

I'd just use a coin on the outside and some good duct tape or aluminum tape to seal it up and tilt the tank so that nipple is pointing down. Then pour enough evap-o-rust in to fill that tube.

You could also use a round file, cylindrical sanding disc, or even sand paper wrapped around a dowel.


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