The cure for rusty-tank syndrome

    It's one thing to have to fight rust that is easily accessible, like on floor pans or quarter panels, where it isn't too hard to get to the problem area.  Nothing is worse than restoring a vehicle, only to find that the fuel tank you have in it is full of loose rust and coated in varnish. I recently fell victim to this exact problem with my VW pickup truck project. I had gone through quite an extensive job in getting this truck to the stage where it was almost drivable, only to be stopped dead in my tracks. If you are unfortunate (or masochistic) enough to have to go through this process, I decided to do a fairly universal "how-to" pictorial of how to go through this process.

    Now, faithful Eastwood readers, I feel that we are good enough friends that I can tell you "how it is" without sugar coating it. This job is going to be messy, dirty, and downright unpleasant. You have to figure, if the gas tank on the inside is rusty enough to cause an issue, the exterior of the tank and it's mounting points have to be that much worse. I found that that was exactly the case on my truck. It seemed like everywhere I looked, under the bed of the truck had surface rust, the outside of the tank being the worst of it for sure. As I dug into it, I found I really had to work to coax the nuts holding the gas tank straps to come off. Luckily I had grabbed a can of CRC Freeze-Off before starting on this. We just started carrying this product, and I will admit, I was a bit skeptical to say the least. I mean, come on, it "freezes" the rust off? But J.R. from our R&D fame assured me that it was the cat's meow as far as rust fighting penetrates go. So I doused the threads on the stud, and the nut itself, a few times with the freeze-off, and let it sit. After working the nut back and forth, a little tapping with a small hammer, and some baby-talk to it, I was able to get both nuts to thread off with out breaking a stud or having to cut the nut off. I would say that the freeze-off gets my approval!

    After assuring that I didn't have to cut off any nuts or mounting studs, I removed the fuel pump lines, the fuel filler hose to the tank, and any associated breather hoses. I then dropped the fuel tank down out of the truck. I've found that your average floor jack is perfect for this job. Once the tank was out, I set it on a fender stand to work on it (not before cleaning the acorns off the top of the tank!). I started by draining the fuel out completely. You can see from the picture of the pre-pump filter, and also of what was left in the drain pan, just how bad the rust and dirt inside the tank was. This was the 4th fuel filter in a matter of a week. Each time I would attempt to drive the truck and hit a bump, the filter would get clogged with more rust. Also note the pictures of the inside of the tank that I shot, if you look closely you can see the piles of rust still in the tank, along with all of that varnish! I tried to knock all the major rust off of the walls of the inside of the tank by dropping some old chain into the tank and shaking it around for a few minutes (I told you this wasn't going to be fun!). Follow all of this up by spraying the pressure washer inside of the tank, trying to flush all of that rust you knocked loose out of the tank.

    After getting the tank out and drained, I realized that I wasn't going to be able to just use our tank sealer kit and restore the inside of the tank, I was going to have to do something about how the outside looked. I decided to choose our Tank Tone Kit. This kit is made to help treat and convert surface rust on the outside of the tank and then you apply a silver coating that is fuel resistant and leaves the tank looking like the day the vehicle left the showroom. I needed to first, assess the corrosion and make sure that I wasn't attempting to restore a tank that possibly would rot out and leak after a year or two. I hit the tank with a wire brush and a metal scraper to get all of the heavy stuff off first. After checking the tank for any thin spots, I started applying the rust converter that is included in the kit. Luckily I have a small 10 gallon tank in that truck, so only one tank tone kit was necessary. I would suggest at least two kits for an average full size car or truck. Because of how extensive the rust was on the outside of the tank, I let the rust converter sit on the tank for a full 24 hours.

    I took pictures below showing how the converter progressed over this time. The last pictures you can really see how the surface has changed color of the rust all over!

    Here is the rust converter working after only a few hours on the rusty tank.

    Now here is after 24 hours with the Rust Converter working on the tank. Notice how much more of the rust has now been turned to a blackish purple color. The outside of the tank is now ready to be primed and top coated!

    This is where the process of restoring an old gas tank really begins to make you rethink why you are doing this project yourself, but I can assure you... if you stick with me, the end result is surely worth it! I used one of our Tank Sealer Kits For Cars, again two or more kits may be needed for larger tanks. I plugged the openings in the tank using tin-foil and appropriate length screwdrivers. This kept the chemicals from getting all over the place. The first step is adding a bucket of our metal wash, which has been diluted with two gallons of hot water. You then shake, and turn the tank to get the metal wash to soak into all surfaces and etch the metal. This is a process that you will be very, very good at by the end.

    After draining and rinsing the tank out, you follow up with a small amount of muriatic acid diluted in a half gallon of hot water. This acid is NASTY stuff, the bottle was smoking when I opened it... that is always a sure sign that this is not a chemical that you want to get on your skin! Again, mix the acid with the water, dump it in the tank, slosh the tank, drain, rinse. You can see how brown and contaminated the liquid coming out of the tank was still at this second step.

    At this point I tried snapping a photo showing how the inside of the tank was beginning to be etched and brought back to clean metal. Pretty neat to see, but tough to photograph!

    In the next step, you dump an entire bottle of fast etch in the tank again, to clean and etch. Once you have drained that all out, you add one small can of Acetone to clean the surface, and help evaporate any other water in the tank. Each of these chemicals are the same as the others, dump in the funnel, slosh around in the tank, drain out.

    After I got the majority of the acetone out, I let the tank sit upside down for an hour to let the chemicals evaporate inside. I then used 1.5 bottles of the tank sealer and sloshed it around in the tank. This time I took much more care, making sure all of the surfaces inside were covered and the sealer wasn't puddling or filling the center baffle. I let the tank sit upside down to avoid this and it also allowed the top of the inside of the tank to get some coverage.

    The sealer fumes are very intense, I got too close and accidentally breathed in the chemicals when trying to shoot the photo of the inside of the tank, and it made me gasp and nearly faint. The lengths I go through to get everyone a thorough DIY article took their toll that night! Crazy stuff. Subsequently I got a headache later on in the evening. Moral of this story is, DO NOT under any circumstances, breathe in, or inhale the fumes coming out of the tank after the sealer has been applied!

    The instructions then called for you to put an air nozzle in the tank and run it at at a low PSI to help dry the sealer and stop it from puddling too much. Since I don't have an air compressor at my home garage just yet, I decided to rig up the exhaust on the shop vac to circulate air inside the tank. I left it on for about an hour, and it definitely seemed to do the trick.

    Once the tank sealer had dried and there were little to no fumes remaining, I applied the Tank Tone to the outside of the tank. This really made a world of difference. I still have trouble convincing friends this is the same tank!

    As they say in the repair manuals, "installation is the reverse of removal," so I lifted the restored tank back up into the truck. Luckily it all fit back into it's home pretty easily, and I was left to admire my handy work, and reflect on the restoration process . As many can relate, sitting back and admiring your handy work can be a catch 22... while it allows you to appreciate the end result of the hard work you put into restoring something, it also allows you to see the imperfections and faults in everything around it! I now noticed all of the suspension parts, and brackets under the truck that had minor surface rust on them. Not to mention the spots on the floor beds of the cab where I had applied our Brushable Seam Sealer and I felt like those spots needed some undercoating to give that OEM finish back to the floor boards, and match the fresh look of the gas tank.

    So that begun the process of again using Rust Converter to treat and convert all of the surface rust, as well as prep the surfaces for top coats. I sealed the treated areas with Rust Encapsulator, and followed up with a top coat of our Satin Extreme Chassis Black. I felt this gave the undercarriage parts a nice understated "OEM" finish, and also gave me the piece of mind that the rust wouldn't be coming back to haunt me years down the road!

    All in all, this was a very tedious, long process. But, I am happy to report that since restoring the tank, the truck is now running well on its new engine, and is very close to being road worthy! I can't wait to hear what the exhaust shop thinks of the undercarriage of the truck when they build my custom exhaust this week!!!

    Keep up the hard work, and as usual, any and all comments, questions, and advice are welcomed here if you leave a comment!!

    -Matt/EW

    52 thoughts on “The cure for rusty-tank syndrome ”

    • Scott A.

      Nice work.
      Can you tell us what you did with the various chemicals after draining them from the tank?

      Reply
      • MattM

        I followed the instructions to neutralize any of the chemicals as mentioned in the instructions: http://www.eastwood.com/images/pdf/10165Q.pdf . Any of the chemicals that I drained out of the tank I put in old empty oil jugs and took them to the local auto parts store. They then had it picked up and disposed of with their old coolant and oil pickups that they have done. Best bet is to call one of your local auto parts stores and see if they offer that service, or can refer you to one that does.

        Reply
    • mmarck

      How much did all this cost?

      Reply
      • MattM

        The retail cost for everything including the items to refresh the undercarriage is about $150. This includes the rubberized undercoating I applied to the areas of the front floor pan that I had previously welded patch panels into.

        Reply
    • ed

      Scott A. go fly a kite. Why ruin a good article with your cynicism? I really wish I hadnt scrolled down to the troll comments.

      Matt, thank you for a very encouraging and thoughtful article. I hope I can display the patience it must have taken to complete this job.

      Reply
    • Bill H.

      I was wondering the exact same thing as I read the article!

      Reply
    • Lionel M.

      I just did this process on my TR6 gas tank, which is about the same size. My experience was similar with the chemicals & general nasty aspects. I also inverted my tank as the sealant dried to keep it from puddling in the bottom. Before it was completely dry, I felt inside the top of the tank where I detected some globs of the sealant. I was able to remove the excess that I could reach with my fingers (very messy). Are there cases where any of the sealant has peeled off? I can see that this could potentially shut down fuel flow. A local professional gas tank restorer told out car club that a lot of his business is restoring tanks that people have coated on their own, only to have the sealant peel off. Have any cases been reported to Eastwood of this nature using your kit?

      Reply
      • MattM

        Lionel, I have heard of a few responses with those issues with many different types of sealer kits. We rarely have any calls about issues regarding that. I know some instances can be confirmed as prep issues, but we are always looking to test and improve upon our products, so any comments or concerns here I will surely pass along to our R&D/Tech team to look into. Thanks for reading!

        Reply
    • Chip

      I want to warn everyone about the gas tank sealer. I would stay as far away from it as possible. I did very careful surface preparation, but the sealer started pealing off in chunks a year or two later and started clogging my fuel filter. I finally had to remove my tank (again) and have it boiled and coated at a radiator shop. The cost was twice what a normal job was to get the Eastwood coating out. At the end of the day, I did the job twice for 3x the cost of just going to the radiator shop to start with. Don't use this stuff.

      Reply
      • MattM

        I have heard of this happening to people, while others have had no issues what-so-ever. Does your vehicle ever sit for extended periods of times (possibly many months to a year or more) at a time before fresh gas could be put in? I will definitely pass this on to our tech team.

        Reply
    • John McKeon

      Very thorough article Matt. Thanks! A nice way to keep track of projects like this is to use Collector Car Companion - car restoration software that let's you catalog your parts and supplies, document your work and organize your photos. I use it on all my projects.

      Reply
    • J. Fyie

      Thanks for the article and approach. I have been working on a motorcycle gas tank for over a year. I want to retain the outside paint, so I have been careful in what I use to rid the tank of gas, sludge, tar balls and rust. Just as a suggestion for a lower risk approach is to use vinegar. It is slow, but will cut rust if you soak long enough. It can be neutralized (baking soda) afterwards. As you say, it takes time and patience. The worse the rust, the longer and more flushes required. I like the sealing approach and assume that is a powerful chemical to do the final seal. Safety first. Try the vinegar on old tool, nuts and bolts. It works, but slowly.

      Reply
    • Ralph F.

      Just a few comments on safety issues. Always when diluting acid, it is "a before w"- pour the acid into water to dilute, not the other way around, which can splatter. Safety glasses or goggles should be worn when using chemicals. I did notice protective gloves, but also a respirator (with carbon filters for solvent fumes) should be worn particularly when working with the tank sealer to avoid that headache (or worse) later on.

      Reply
      • MattM

        Very good information Ralph! I was in fact taking much care when mixing the acid. I did add it into the water to avoid any splashing. I also threw my "work coat" on when I was dumping it into the bucket to mix and while I was stirring it. Just to save any possibly splatter. Thanks again, all good points!

        Reply
    • Patrick

      I thought this was an awesome article as I've always wondered how I'd go about cleaning and then sealing up a gas tank full of crud.

      I don't think it's cynical to ask where the drainage went. That was my first thought as I looked at the picks. It's a legitimate concern and therefore a legitimate question. I appreciate the question and the answer

      My second question was gonna be: how much did this cost but someone beat me to it.

      Thanks for a great article

      Reply
    • Vincent L.

      Matt,
      Nice job, and it's refreshing to hear a story about how it actually went, rather than a "wish how it went". Makes it easier to assess if you actually want to attack the problem, in a good way. As for ed, it's people like you that spoil a good source of information and response.

      Thanks Matt and Scott.
      Vince

      Reply
    • James Roundtree
      James Roundtree August 10, 2010 at 7:59 am

      You just wasted all your time and money. Within 2 years, all of that "sealer" will have to be flushed from your tank. It is best to send your tank to a place who provides this service in an industrial manner. Been there and done that!

      Reply
      • MattM

        We have had a number of employees here that have had their sealer kits in their vehicles for many years with no issues. Possibly a issue with prep? Hard to say really, but I did not have the time, or the money to have it done professionally as I was swapping the engine out in the truck the following weekend and needed the tank to be refreshed ASAP. Not to mention I am a bit stubborn and apparently like doing things the "hard way". Thanks for the reply, I'll keep my eye on the tank for any issues down the road!

        Reply
    • Scott

      Will the products mentioned in the article ship to Hawaii or are there hazmat issues? I've done the exterior of my tank and it looks great, now I'm wondering about the inside.

      Reply
      • MattM

        Some portions of HI we can ship to, although it can be quite expensive to ship due to Haz-Mat issues. There is some exclusions to that apparently. Your best bet is to give our customer service department a call and give them your full address, and we can give you an idea of what the cost would be.

        Reply
    • Acemoose

      Yeah I wondered too about those chemicals too -- the manufacturer should have posted information about proper disposal -- did they? If not, did you contact your county government to find out the proper method of disposing of those chemicals? (Not in the storm drain, I hope!)

      Reply
      • MattM

        With any of these tech articles I write, I have to weigh the importance of including relevant information and also still keeping it interesting. I decided to leave out every little detail of how I drained and disposed of the chemicals as the article began to get a bit too long. As I mentioned to someone else, I ended up contacting my local auto parts store, and they offered to dispose of the used chemicals with their current disposal service. We do include any information on disposing/handling any of the chemicals in our instructions which I also posted a link to in another comment. Hope that helps!

        Reply
    • Ed - GA

      This is interesting and I would do it if the vehicle was an oddball and no parts are made for it. New tank for my truck was $70. A can of paint for $5 and I was done. I just can't see doing all that work if new tanks are available. No dangerous chemicals to handle or have to dispose of later. Paint it and bolt it in, done.

      Reply
    • Tony Q

      I'm not sure why a previous comment says that you will have to flush it out after a couple of years when I did my tank with eastwoods product in 1993 and have not had it out since. Still going strong!!!

      Reply
    • JimC

      Matt,
      Great write-up and the pictures made every detail more understandable. Regarding the varnish buildup in the tank, how was this removed, or if it was not warranted, what product would be used to do so?

      Thanks,

      Reply
      • MattM

        The succession of chemicals you use in our kit breaks down the varnish and when rinsing it out, will flush it out. Hope that helps!

        Reply
    • billy

      There's an easier way to remove the inside rust! Fill the tank with water, add 1 cup of Arm&Hammer laundry detergent that has baking soda in it. shake the tank a little to mix it! Now using a very large spike nail insulated at the top and bottom,so it does not contact the tank,insert the nail in tank , attach the positive clamp of a 12volt battery charger, to the top of the nail. Now attach the negative to the tank itself! Turn on the charger! You will almost immeadiatly see the rust being broken loose and coming to the top! Do this 2 times for about 8 hours, changing the fluid in between! I have been doing this for years , and it works great!

      Reply
    • Tom Ballou

      I'm not sure about Mr. Roundtree's experience, but I used a double kit to refinish the two fuel tanks in my Sunbeam Tiger about 10 years ago. It is still doing fine and unfortunately, I have to admit it sits for months at a time with the fuel just aging in the tanks (I do add Stabil). I check the filters every few hundred miles or so and so far, I have seen no flaking or other indication of sealing material failure.

      Reply
    • Brad Howren

      Did this to the tank off my FSJ pickup several months ago. If you have a tank with a lot of varnish in it use the acetone first. It was the only thing that would remove it, even muriatic acid wouldn't touch the stuff. Gave the tank a good coating using a dental mirror and flashlight to varify 100% sealer coat. Now only time will tell if the stuff stays put!

      Reply
    • Boyd Roberson

      I have used this product on three vehicles so far with excelent results (but a lot of hard work). The first one was a 1967 VW around 1996, and I've had no problems at all. I also used it on a new tank that I built for a VW powered Trike (to try and eleminate any future rust problems), and on a 1967 VW bug.

      Reply
    • Brad Howren

      Used the kit with extra bottle of sealer. Followed instructions to the letter. After three days of sloshing, soaking, and flushing went to the acetone. Dissolved the varnish in a matter of minutes. After sealing let sit in sun for three days till all hint of fumes were gone.

      Reply
    • Eric P.

      @MattM
      Great Write up!
      Only thing I'd add would be: I've found an easy and very effective way to seal necks/barbs on the tank is to stretch a double-folded latex glove over the neck and triple-wrap with a rubber band.
      Viola! Water-tight seal!

      Reply
      • MattM

        Very great idea! Wish I would have thought of that ahead of time, probably much more efficient than my method for plugging the holes!

        Reply
    • Mark B

      I see a Scirocco in your garage!

      Reply
      • MattM

        Good Eye! I have a 77 Scirocco that is a driver/weekend car, and that one in the garage is my roomate's 87 16v Scirocco project. Unfortunately he is a bit slower on restorations than I am, and it won't be done for some time.

        Reply
    • Bruce Flinn

      Matt, nice write up. Last summer and fall I did basically what you did but had to go a little further as far as the suspension went on my 1974 Pinto Gas Tank restoration. I was lucky and didn't have to seal the inside of the tank as it was very clean and rust free. Here are photos and descriptions on my flickr account that show what I went through: http://www.flickr.com/photos/bruceflinn/sets/72157624702493716/

      Keep up the good work and the great examples of DIY's to follow.

      Reply

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