dllubin
Don
I could see the element close up and it looked pretty normal. I'm not sure there was E85 the last time I filled the tank in that car.
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Need to clean fuel tank - AGAIN
- Thread starter dllubin
- Start date
dllubin
Don
Yesterday, I ran about a quart of gasoline through the fuel pump to clean it out. The first few ounces looked like Texas crude. The Fram pre-filter evidently did not catch much. Also found that the carbs got some of the viscous liquid and it clogged the float valves - probably a good thing as it kept the junk from propagating much further. Going to clean both carbs and connect the fuel system to an outboard motor tank and see how it runs. If OK, I'll get the car back up in the air to pull the tank.
Dr.Jeff
True Classic
Today I began the phosphoric cleaning of the tank. The acid that was readily available at my local builders supply (inexpensively) is a pre-diluted solution (40%). At this dilution you could use it full strength as packaged. However the X's tank is about 13 gals, so it would get a bit expensive to do that. Instead I used 2 gals acid and 3 gals hot water. That means I will have to do one end of the tank, then flip it on one side, then the other side, and finally the other end. Furthermore at this dilution it will have to sit overnight to clean a tank as bad as this one. So about a 4 day process. Not for the impatient I agree, but it is the most effective method and will save this tank. I'm the type that would rather spend the time and a few dollars this way than spend a lot of money for a new tank (which I've read has its own issues).
To do the phosphoric cleaning process:
1) Clean as much unwanted material out as possible with plenty of rinsing, physical agitation (eg. shake the tank around with a piece of chain inside if it is that bad), and a degreaser rinse to eliminate any oily coatings (dramatically slows the acids effectiveness).
2) Plug all openings with whatever it takes. Here is what I had on hand; some plastic/vinyl hose caps/plugs (red arrows), a piece of old rubber inner tube with a hose clamp (blue arrow), and a plumbing temporary plug (yellow arrow). The plumbing plug is nice because you can take it in and out easily.
3) Prop up the tank to whatever position you wish to clean. In the above photo it will clean the bottom third or so. With one plug removed (yellow arrow), add the hot (adding heat energy will help the chemical reaction) water to the tank first, then using a funnel pour the acid in second. Keep the garden hose on hand to rinse any spillage and wear appropriate safety gear.
4) Secure the removed plug and shake the tank around to help mix the solution. Then loosen one of the plugs at the top (yellow arrow one in this case) to allow it to vent. Otherwise it will build pressure as the chemical reactions take place and may blow off one of the plugs.
5) Let it sit, in this case overnight. The length of time required will depend on how bad the tank is, what percent of acid solution you have, and the temperature. Occasionally shake the tank around to agitate and keep the solution mixed.
6) Tighten the loosened plug at the top and turn the tank to a new position to clean another portion of it. Loosen another plug to allow venting again. Repeat this until all areas inside are cleaned. The inside surfaces will get a grey color to them when they are clean. This is the phosphate coating that is left from the phosphoric acid's reaction and provides a great protective coating from future rust, etc. Other acids will not do this and that is the main reason for using phosphoric acid. Plus it is a safer acid to work with than most others.
7) Drain the solution from the tank. Save it because it can be reused several times for all types of cleaning and metal prep. Then rinse the tank using some water mixed with baking soda to neutralize it. Here is where the remaining phosphate coating is great, because without it any rinse with water would immediately start new rust formation on the fresh bare metal. Dry the inside thoroughly and it is ready to be put back in the car.
As you can tell from the description of the process, it should be done with the tank out of the vehicle. It is a bit physical (a tank with liquid inside is a little heavy) and takes time for the acid to work. But the general prep and overall process is not difficult.
I'll try to get a picture of the inside when it is done. But I won't risk getting my medical borescope dirty so I might not be able to show much.
To do the phosphoric cleaning process:
1) Clean as much unwanted material out as possible with plenty of rinsing, physical agitation (eg. shake the tank around with a piece of chain inside if it is that bad), and a degreaser rinse to eliminate any oily coatings (dramatically slows the acids effectiveness).
2) Plug all openings with whatever it takes. Here is what I had on hand; some plastic/vinyl hose caps/plugs (red arrows), a piece of old rubber inner tube with a hose clamp (blue arrow), and a plumbing temporary plug (yellow arrow). The plumbing plug is nice because you can take it in and out easily.
3) Prop up the tank to whatever position you wish to clean. In the above photo it will clean the bottom third or so. With one plug removed (yellow arrow), add the hot (adding heat energy will help the chemical reaction) water to the tank first, then using a funnel pour the acid in second. Keep the garden hose on hand to rinse any spillage and wear appropriate safety gear.
4) Secure the removed plug and shake the tank around to help mix the solution. Then loosen one of the plugs at the top (yellow arrow one in this case) to allow it to vent. Otherwise it will build pressure as the chemical reactions take place and may blow off one of the plugs.
5) Let it sit, in this case overnight. The length of time required will depend on how bad the tank is, what percent of acid solution you have, and the temperature. Occasionally shake the tank around to agitate and keep the solution mixed.
6) Tighten the loosened plug at the top and turn the tank to a new position to clean another portion of it. Loosen another plug to allow venting again. Repeat this until all areas inside are cleaned. The inside surfaces will get a grey color to them when they are clean. This is the phosphate coating that is left from the phosphoric acid's reaction and provides a great protective coating from future rust, etc. Other acids will not do this and that is the main reason for using phosphoric acid. Plus it is a safer acid to work with than most others.
7) Drain the solution from the tank. Save it because it can be reused several times for all types of cleaning and metal prep. Then rinse the tank using some water mixed with baking soda to neutralize it. Here is where the remaining phosphate coating is great, because without it any rinse with water would immediately start new rust formation on the fresh bare metal. Dry the inside thoroughly and it is ready to be put back in the car.
As you can tell from the description of the process, it should be done with the tank out of the vehicle. It is a bit physical (a tank with liquid inside is a little heavy) and takes time for the acid to work. But the general prep and overall process is not difficult.
I'll try to get a picture of the inside when it is done. But I won't risk getting my medical borescope dirty so I might not be able to show much.
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dllubin
Don
Nice write up Dr. Jeff. Don't blame you on the borescope. I stuck my fancy 1,000 lumen flashlight down there and it took quite a while to clean up even though it wasn't supposed to be touching anything. What are you planning on using for the degreaser? That could be my greatest need (actually a de-"old gasoline deposits" is what I need). I got one carb cleaned today, plan to do the other tomorrow. Still have not opened the sender and taken a look but I have images of something similar to that 1950s movie creature "The Blob" floating around inside. So far nothing in the way of visible particles, just this dark, petroleum based mass from outer space!
Dr.Jeff
True Classic
The degreaser is just to remove any oil film before putting the acid in. So a common solvent like paint thinner would do. You already accomplished this step as part of your first cleaning. No need to go back, especially with your tank being in decent shape compared to mine. I think if you pull it and give it a acid wash it will get rid of the remaining gunk. And yours won't require the long soak time mine does. Depending on the concentration you use you might be able to get it clean in a couple hours. Mine was bad enough I considered a more aggressive approach; first a quick soak with a very strong acid followed by a rinse and then soak with the phosphoric. It would have reduced the time required for the phosphoric significantly. I've restored some vintage motorcycle tanks that were really bad (bikes tend to get more water in their tanks) with that combination of acids.
MikeHynes
True Classic
Thanks for the excellent write-up on the use of phosphoric acid to clean up a rusty fuel tank Dr. Jeff. The acid is a good way to remove rust from parts but I would offer a bit of advice. Don't use it indoors if you can avoid it, the fumes are nasty. Also, don't let the fumes get anywhere near any metal things that you don't want to be attacked by the acid fumes. I set a pan (plastic) of nuts/bolts outside in front of my garage door and - duh - the fumes attacked the garage door. Don't do stupid stuff like that!
I've used Evapo-Rust on fuel tanks with excellent results. It's not caustic like acid, but it's pretty expensive and I don't think it leaves any kind of protective coating. Evapo-Rust does offer a product that is suppose to provide a protective coating, but I don't know how gas would affect it.
Another note of caution, always use a pre-filter before the fuel pump.
I've used Evapo-Rust on fuel tanks with excellent results. It's not caustic like acid, but it's pretty expensive and I don't think it leaves any kind of protective coating. Evapo-Rust does offer a product that is suppose to provide a protective coating, but I don't know how gas would affect it.
Another note of caution, always use a pre-filter before the fuel pump.
dllubin
Don
I finished cleaning the carbs and fuel lines today. Unfortunately, gasoline run through the fuel pump is still coming out slightly darker than it went in. It is a different mechanical style pump than I had been using on the 1300. It does not have the center bolt you unscrew to remove the cover and access the screen. In fact, I don't know if it has a cleanable screen. The top is a two level setup with the input nipple on the top level and the output nipple on the lower level. Doesn't match any photos in the 4 X1/9 manuals I have. I might swap it out for a spare I've got with about 20K on it. I've already run more gasoline through it than I wish to invest. My guess is that it will have to be opened if that is possible. There is probably a blob of that crap in there that is out of the way enough not to get flushed, but is slowly dissolving in the fuel passing through. Since I've got to get the car in the air to pull the tank anyway, I'll do that next to make it easier to pull the pump.
Dr.Jeff
True Classic
I do not think you have any "blobs" of stuff in the pump or tank. I think what you are seeing is discoloration or 'staining' of the fuel resulting from a chemical reaction. The accumulation of old fuel, etc that was in the tank is slowly dissolving and causing the new fuel to change color. But that does not necessarily mean it is harmful. This last cleaning of the carbs and pump, did you observe any actual particles of matter? Or just the color change? Keep in mind that contaminants physically large enough to cause problems will be visible on close examination. Therefore I would not be too concerned with the pump or hoses or carbs at this point. Just give the tank one more cleaning to help remove any residual film that might be on the walls and be done with it...you will be fine.
dllubin
Don
Well initially I was getting blobs of stuff coming out of the pump. Now it is down to the point where clear gas goes in the pump and comes out with a bit of a brown tint to it. I've got everything else in the system downstream of the sender so that clean gas goes in and clean gas comes out. Not sure I want to connect that pump up until I see what is in there. It is definitely not normal deposits in the pump getting dissolved and put in solution. Too much material going into solution too fast for that.
dllubin
Don
Hi Denny:
I think I will have a better idea of of whether I need a new tank after I get the old one out. I have not seen much rust so I am hoping I can get the mess out that fouled the fuel system. I will keep you posted on the situation.
Thanks,
Don
Dr.Jeff
True Classic
I misunderstood, I thought it was only discolored. Was it the same from the tank and the pump? Curious what the "blobs" looked like? Gelatin consistency or hard pieces? Tiny bits or large lumps? A better description might help to compare it to issues I've encountered before and give some ideas what to do.
dllubin
Don
Somewhere between gelatin to viscous blobs of material the can be small "rice" sized and can also stick together as a mass. I think the only way that the fuel pump could be soiling this much gasoline is that it has a collection of junk that is slowly going into solution. If it was one of the more common Fiat pumps with a removable screen, I'm pretty certain that it would be fouled. However, I'm not familiar with this style of mechanical pump so I don't know what is inside. I have not checked it out in detail, but It is not clear that it is serviceable like the more common style.
Dr.Jeff
True Classic
I finished cleaning mine today. Came out nice considering I took some short cuts doing it. This tank had a very heavy build up of a hard crusty accumulation. I knocked a lot of it loose before giving it the acid wash, but really I should have used a more aggressive 'preclean' method. One way is like I said previously and drop a length of metal chain inside then shake it vigorously so the chain breaks up all the stuff stuck on the walls and bottom. Also this tank was on the border of needing a stronger acid first, followed by the phosphoric acid. Phospho really isn't that strong but leaves the phosphate coating I described. So in bad cases it is easier to do a two step method by using a strong acid first. But you need to watch out that it doesn't burn through the tank.
Now I'll make sure it is completely dry and do a final solvent rinse. Some acetone is a good way to dehydrate it, plus it acts as a final rinse before putting the tank back into service.
One thing we haven't discussed is the pick up screen (filter) that is inside. If you have a carby tank the screen is on the end of the fuel level gauge/pick-up tube. That makes it easy to inspect and replace. But if you have a FI tank the screen is inside, on the end of the barb that feeds the pump. This one is impossible to get to without cutting an access hole in the tank. But those screens usually are very crusty and clogged with crud and should be replaced or at least removed. Being made of a very soft brass like material, it will get eaten away by the acid treatment if you have a strong enough concentration and let it sit long enough. This is a good thing because it resolves the problem of getting it out of there and you can replace the pre-filter that's just after the barb on the outside (between the tank and the pump). That was the case with my tank, the screen was really bad. I even have a new replacement thinking I would have to cut open the tank and change it. But now that it is completely gone I won't cut the tank and use a good pre-filter on the outside.
Now I'll make sure it is completely dry and do a final solvent rinse. Some acetone is a good way to dehydrate it, plus it acts as a final rinse before putting the tank back into service.
One thing we haven't discussed is the pick up screen (filter) that is inside. If you have a carby tank the screen is on the end of the fuel level gauge/pick-up tube. That makes it easy to inspect and replace. But if you have a FI tank the screen is inside, on the end of the barb that feeds the pump. This one is impossible to get to without cutting an access hole in the tank. But those screens usually are very crusty and clogged with crud and should be replaced or at least removed. Being made of a very soft brass like material, it will get eaten away by the acid treatment if you have a strong enough concentration and let it sit long enough. This is a good thing because it resolves the problem of getting it out of there and you can replace the pre-filter that's just after the barb on the outside (between the tank and the pump). That was the case with my tank, the screen was really bad. I even have a new replacement thinking I would have to cut open the tank and change it. But now that it is completely gone I won't cut the tank and use a good pre-filter on the outside.
Dr.Jeff
True Classic
There was something like that in mine also. But I had so much crud in general it is difficult to tell what was what. I'm guessing your tank might have had a layer of a similar gunk as mine had, only not nearly as thick. Mine smelled quite foul so the gummy gunk could be a algae growth of some type. In your case the prior cleaning likely broke it up so it is coming out a little at a time now.
dllubin
Don
My tank had the smell of old gasoline really bad - kind of a cross between really old oil based paint and vomit. I spilled a very small amount on the ground last fall and it took months for the smell to go away. The initial cleaning got rid of smell in the tank (more or less). There was no trace of the screen on my sender. Only the barb that it was supposed to be attached to. That was one reason to add the pre-filter. Too bad I used that crappy Fram filter that did not block much. I think the fuel pump may have filtered as much. I'm going to stick with those WIX 33001 filters from now on. The one I had on after the pump saved the carbs from a world of hurt.
Dr.Jeff
True Classic
After my earlier post about my tank I went back out to finish drying it. I noticed that there was still a little bit of crud in a couple of spots. Remember I said that I cut some corners...paying the price now. So I decided to put the acid back in for a little longer.
Looking more at the goo that came out earlier (with the acid wash), it reminds me of the tar I had to clean out of another tank (non-Fiat) where the fuel had dissolved some rubber components inside. It's a viscous sticky oily tar that will smear on something then won't come off. Only this time it was more of a rust color rather than the black stuff before. What's odd is it will dissolve in the acid solution when agitated, to the point you don't really notice it - just looks like dirty fluid. But when the solution is allowed to sit still for awhile the goo separates back out and floats around in suspension. It's that coagulated state that will stick to things and make a mess. I wonder if something like that might be going on with yours?
Looking more at the goo that came out earlier (with the acid wash), it reminds me of the tar I had to clean out of another tank (non-Fiat) where the fuel had dissolved some rubber components inside. It's a viscous sticky oily tar that will smear on something then won't come off. Only this time it was more of a rust color rather than the black stuff before. What's odd is it will dissolve in the acid solution when agitated, to the point you don't really notice it - just looks like dirty fluid. But when the solution is allowed to sit still for awhile the goo separates back out and floats around in suspension. It's that coagulated state that will stick to things and make a mess. I wonder if something like that might be going on with yours?
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dllubin
Don
It was working fine for about a week before the "blob" got sucked into the fuel line. It was never connected before the tank was cleaned.
dllubin
Don
Dr. Jeff:
That black stuff sounds similar to what I've been getting. I pulled the tank today and got a better look inside:
You can see where some of that varnish like stuff has come off the walls down where the fill line was about a week or so ago. Some of it is floating on the remaining fuel. Good thing I pulled the tank. I found the rubber hose between the filler and the tank was completely rotted in the center with about a 350 degree tear around the circumference. That is the only bad piece of original rubber on the car that I have come across.
Some good news on the fuel pump: It is pumping clean now. Not sure this pump is serviceable like the more common ones:
After seeing what the inside of my tank looks like, what do you think would be a suitable next step? I was thinking perhaps some strong solvent to get the varnish and gunk followed by phosphoric acid to treat the surface rust. Right now I've got the gas I used to flush the fuel pump (it is semi-clean) sitting in the bottom of the tank. Hopefully, it will loosen things up a bit. I may also see if can knock things loose with the old nuts, bolts, chains trick. It would be good to find something to keep the tank agitated for a reasonable period of time. I've got a bunch of yard cleanup to do (it is redwood leaf shedding season) so I was thinking of loading the tank up with hardware and solvent, and then strapping it to my wood chipper. A few hours on that thing may be as close to an ultrasonic cleaner as that thing is going to get. I read on one site that someone did a similar trick using a cement mixer. That would provide rotation and vibration whereas the chipper is vibration only (but lots of it - metal fatigue an issue with some sheet metal parts). I might also see about getting more aggressive with the pressure washer. With the tank out, I think I can reach more places inside.