Mike the Radiator Man's
Tech Tip #4 , Fuel Tank Restoration
The early Fairlane (62-67) does not have a source for new fuel tanks at this time. Crites makes a fiberglass tank, but I suspect it is not D.O.T. hiway legal in many states. We need to look at properly repairing the tank we have.
I have been repairing fuel tanks for may years and will not touch on the subject of welding or soldering on fuel tanks, for safety reasons this should only be attempted by knowledgeable experts. If your tank needs patched or welded, please take it to your local radiator shop.
Before attempting removal and repair of your tank, make sure you can dispose of the old fuel properly. Never drain a fuel tank in an area near open flame or sparks.
If the inside of your tank is clean and rust free, but you would like to install a tank liner to keep it that way, you can effectively remove the petroleum film from the metal by using 2 cups of liquid Tide Laundry Detergent and water. Do not use the powder type, you will never get it all out.
Cause of Fuel Tank Problems
Rusty fuel tanks (internally) are a common problem for many of us. Some of our project cars may have been setting for many years before we acquired them.
A partially filled fuel tank can cause far more damage than a full one. The air space above the fuel reacts to temperature changes allowing water vapor to condense and create droplets of water on the top of the tank. This will cause the protective plating on the tank metal to be destroyed to the point that bare steel is exposed. Bare steel will rust quit rapidly especially in the presents of water and corrosive acids created by decomposing fuel.
Old fuel is very destructive. It turns to a varnish (tar like) substance, and creates acids when mixed with moisture. Dried fuel can be broken down by our modern fuels. They contain injector cleaners, but the varnish tends to come off in small chunks that plug up filters.
Rust will start to flake off and plug fuel filters. If you think you can flush out a rusty tank and get by, you are fooling only yourself. It will come back.
Many of us have seen the promised cure in a can that repairs worn out engines, give 25% fuel economy increases, or fix burnt up transmissions. Please be advised that most fixes in a can rely on a very human trait of "wishful thinking, over ruling common sense" wanting it to work. This applies to fuel tank fixes also. With most repairs on our cars the real axiom should be "do it right the first time, and forget it".
Repair Process
#1 The tank must be cleaned and derusted to bare metal. This best left to the pros. like RediStrip. They can remove dried fuel, rust (inside and out), under coating, rust proofing, and dirt in one operation for about $75.00. They have another treatment at additional cost that will discourage the metal from future rust.
I have had many tanks brought in that have large globbs of tank sealer in them rattling around like a rock, because it would not stick to rusty metal. If you are considering the old home remedy of pouring muratic acid in the tank to remove rust, I strongly advice against this method. The metal can be derusted this way, but the acid will leave the tank even more prone to rust. The acid must be flushed from the tank with water to neutralize it. Metal that has been etched with acid will immediately start to rust again right before your eyes.
#2 Once you have a clean dry tank (dry is very important) a liner coating can be installed. Use only high quality tank sealer, such as POR-15, or Bill Hirsch products. They are available through Hemmings Motor News.
The liner has 2 functions, seal the bare metal from the air, and seal up any tiny holes that may have opened up in the derust bath.
Pour the liner/sealer through the float/pick-up opening using the recommended amount (usually about 1 quart) of tank liner for the Fairlane tank. Use duct tape ( more than one layer may be required) to close off the filler neck and float/ pick-up openings. Rotate the tank end for end and side to side , making sure to coat all internal surfaces. Let the tank rest between rotations log enough to allow the sealer to flow from end to end. Don't forget to allow the sealer into the filler neck, as this can rust up again if not properly coated.
Open the float/pick-up hole and visually check to see if there is complete coverage. If so, pour
the excess sealer back into the can.
Allow the tank to dry over night. Inspect the interior for total coverage. If the sealer looks to thin or you did not get complete coverage, apply a second coat and allow to dry.
Shopping for Used Fuel Tanks
When looking for used tanks, remove the float/pick-up assembly so you can look inside. Run your finger around the inside to feel it. Does it feel like sand paper or does your finger have rust on it? If it does, this is not a good choice. A mirror and flash light can give even more insight to the true condition. If it is not acceptable to use as is, then the price should be very cheap. Be cautious, don't buy someone else's junk.