Rust in gas tank

[red71c10]

Truck ran fine when I first started driving it a month or so ago. It had been sitting for at least two years before I bought it. After putting gas in it a couple of times it started running rough. Cleaned the brass "in carb" fuel filter and it ran good for a short time. Checked the filter again and it was gunked up with rusty sediment. I need some opinions on what to do next, should I:

1. Have the tank flushed out. Will I need to have the inside coated?
2. Flush it out myself and if so, how.
3. Buy a big in line fuel filter - cheapest, but will it work?
4. Replace the tank
5. Do this instead - (fill in the blank ____________________)

[otsenre]

I also had one that sat for long time. I took tank out, wnt to checker auto, bought some sort of seafoam cleanser, let it sit for a couple hours, then I took my power washer,(with tank upside down so will drain as you wash) and was surprised how it cleaned up tank. Take your air nozzle to it till its good and dry.

[kelsfine69]

We took ours out to the local rad shop, Cleaned and some sort of coating( I think? I will Have to ask my dad) and for 50 bucks. Problem solved

[Jim_PA]

I fought mine for 2 years by using 2 filters (one inline, one in the carb). It never cleared up. When I replaced the tank, the inside of the old one looked like a relic from the Titanic. Never in a million years would it have cleaned itself out.

Do something about it -- flushing the tank is probably what I'd do if I could start over.

[macyak]

I would drain and clean the tank, then be sure and replace the filter/strainer on the end of the sending unit inside the tank. The sending unit should have a strainer on the end, most of these are rotted off and you have an open ended fuel line sucking up anything that is floating inside the tank. The fuel is sucked up from the bottom, so replacing the strainer in the end of the sending unit should keep most if not all of the rust out of your fuel line. As a precaution I would also run and inline filter after the tank and before the fuel pump....All I did was replace the strainer on mine and used an inline filter. No more issues.

[Longhorn Man]

replacing the strainer and not addressing the rust is a good plan if you want to sit on the side of the road.

Pull the tank, drain it, and take it to a radiator shop. They'll clean it, and if it needs a liner, they'll do that too.

[70cst]

Originally Posted by Longhorn Man

replacing the strainer and not addressing the rust is a good plan if you want to sit on the side of the road.

Pull the tank, drain it, and take it to a radiator shop. They'll clean it, and if it needs a liner, they'll do that too.

X 2 The question is do you want a band aid or a fix? If there is rust it will continue to flake off causing you issues until you nutralize the rust in some form or fashion. JMHO

[mr48chev]

Some radiator shops won't let a gas tank in the door for even a cleaning.

I'll agree though that you should drain and pull the tank and either wash it out with a pressure washer or have it cleaned by a radiator shop or??
I put an inline filter between the tank on every one of my older rigs and that has saved me more than once.
One problem with these 35+ year old trucks is that quite often somewhere in their past they either sat or were run without a gas cap for a period of time.

[jbristo67]

Originally Posted by red71c10

Truck ran fine when I first started driving it a month or so ago. It had been sitting for at least two years before I bought it. After putting gas in it a couple of times it started running rough. Cleaned the brass "in carb" fuel filter and it ran good for a short time. Checked the filter again and it was gunked up with rusty sediment. I need some opinions on what to do next, should I:

1. Have the tank flushed out. Will I need to have the inside coated?
2. Flush it out myself and if so, how.
3. Buy a big in line fuel filter - cheapest, but will it work?
4. Replace the tank
5. Do this instead - (fill in the blank ____________________)

Relocate the tank under the bed

[Longhorn Man]

I don't recomend a filter between the tank and the pump. This reduces the pressure in the line which lowers the boiling point. This can create a vapor lock situation, or, make a current one worse.

[red71c10]

Originally Posted by jbristo67

Relocate the tank under the bed

I would like to do that, but don't have the $ponduli right now. It took a lot just to get it driveable and I won't really have any extra ca$h for the truck right away.

[VanceH]

I was told at auto zone there is a something you can pour in the tank after you drained and cleaned it to seal it?? I have two filters as well i get about 100 miles then have to replace both for the truck to run.

[macyak]

Re: Rust in gas tank

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I don't recomend a filter between the tank and the pump. This reduces the pressure in the line which lowers the boiling point. This can create a vapor lock situation, or, make a current one worse.
__________________
70 Longhorn
72 suburban

I am talking about the stock tank with mechanical pump not an electric pump. Mechanical pumps work off of suction not pressure. The pump is what makes the pressure. So a filter before the pump makes no difference unless it is plugged. If the filter is plugged then the pump doesn't have the fuel to pump anyway.

[OregonC20]

I replaced mine with a nice, clean tank that I purchased at a local junk yard for $25.00. I also bought a brand new sending unit for $38.00 locally.

[Longhorn Man]

Originally Posted by macyak

I am talking about the stock tank with mechanical pump not an electric pump. Mechanical pumps work off of suction not pressure. The pump is what makes the pressure. So a filter before the pump makes no difference unless it is plugged. If the filter is plugged then the pump doesn't have the fuel to pump anyway.

When ever you are sucking on something, there is neg pressure. Any pressure reduced from atmospheric pressure, lowers the boiling point of what ever fluid is in that line.
When you pressurise something, it raises the boiling point. Like the cap on the radiator, or the ball on the top of an old school pressure cooker that mom used to use back in the day with a pot roast.
Electric pimp, mechanical pump, doesn't matter. The type of pump does not have any effect on science.
Any resistance puts a restriction on the suction. Even a brand spankin new silter, decreases flow, by causing a restriction. Put a few particles of rust in there, and it gets worse. Put a bunch or rust, and it gets even worse.
I've been wrenching on cars, trucks, M! tanks, heavy eqiuipment, and over the road trucks my entire adult life, which granted, is only since 92 or so, but none the less. I have never seen a mechanical pump go bad from specs of rust. If that was an issue, then GM, Ford, Dodge, and all the others, would have put filters directly before the pump. The screen on the pick up tube seems like a good idea, but in reality, it is more of a headache than it is worth... why should you have to remove the sending unit, and drop the tank in most aplications, to replace a filter. I personally remove this screen on every carb'd engine I have ever had with the exception of my suburban, and that is only becouse I haven't had a reason to drop the fuel tank yet, and I have never ever had a fuel pump go bad on me. Not a mechanical one anyways.

[americanmusc1e]

Originally Posted by VanceH

I was told at auto zone there is a something you can pour in the tank after you drained and cleaned it to seal it?? I have two filters as well i get about 100 miles then have to replace both for the truck to run.

POR15 makes something, I think, Probably expensive though

[Longhorn Man]

POR does make a pour in liner, but there are better products on the market. This is one area where I personally give POR a thumbs down. I used it in my tank on the longhorn and it has only held up for 4 or 5 years now. There's another product we use at work (in house rad shop) I think it's called red kote.
Knowing what all is needed to do it properly, I highly recomend farming the job out.

[Wootdog]

If you are dollar poor, you can try the following which is what we used when I was growing up. Get the extra gas out of the tank. Remove it. Get a water hose. Turn the tank upside down after you fill it up with water. Once you get the majority of the rust out, Let the tank sit in the afternoon sun for a couple of hours. Then use your air hose and compressor if you have one. If not, Like I said before turn it upside down. Get all the water out. Reinstall it. Put gas back in. Hopefully about a quarter tanks worth. Add a few pints of rubbing alcohol. Six to eight is what we used. It is really cheap. It is the primary ingredient in gas additives. That will take the majority of the water/condensation out of the tank. I would then put a inline filter between the fuel pump and the carb. Then monitor it. If that doesn't work use the radiator shop when the duckets allow.
Kerry

[UltraBlue71]

After you address the rust, LMC sells a tank lining product you could use, then install one of those clear plastic filters between your pump and carb so you can see if anythings plugging your filter when ya check your oil, you might want to replace the filter in your carb too!

[So.Cal.Super]

Originally Posted by Longhorn Man

I don't recomend a filter between the tank and the pump. This reduces the pressure in the line which lowers the boiling point. This can create a vapor lock situation, or, make a current one worse.

I read this after I put a very nice very expensive filter on my truck at the same time I replaced my fuel pump. I only run premium gas from good stations and I started to notice at W.O.T. between second and third my truck would buck and jump. well I put 2 + 2 together with what I read and after I got 5 I said ok this can happen to me. I still let it go because I wasn't that worried about it. then it started happening at lower speeds and I still let it go. Then one day I went to pull out of my driveway and it died. Its not fun to try and push one of these back in the driveway by yourself.

After pouring some gas in the carb to start it and back it up in the drive way.
I started trouble shooting and came to find out as soon as I bypassed my pretty fuel filter she fired up and ran like normal.

Yes I have heard the stories of I have ran them with no problem, Sadly I am not one of them.

[Longhorn Man]

there is absolutly no reason to do it, and one very good reason not to.
Reason;

Its not fun to try and push one of these back in the driveway by yourself.