Gas Tank Repair

Out of all the repairs usually necessary in the restoration process, there are two system repairs that I regard as top priority. While there are others as well, it's these two that I feel deserve extra attention to details. The fuel system & the electrical system on any vehicle pose serious threats to the property & to the operator if not maintained, properly repaired or fully understood by the owner/operator of the vehicle. This article is intended to call your attention to the fuel system & in particular repairs to gas tanks. It is not intended to give you a detailed instruction on "How TO" but it is intended to make you aware of how dangerous the fuel system can be on these vintage machines if they are neglected or not properly repaired or maintained.

Every owner/operator should be on the look out for fuel & fuel vapor leaks from aging carburetor's, gasket's, fuel lines, filters & any other typical component part in the system. And the largest part of the system, your fuel tank. The tanks on vintage L & G tractors pose a number of potentially serious safety hazards which I hope to make you aware of here in this brief article. And I do hope that you will give things further thought after you have read my ideas on this subject. First let me address general fuel tank repairs & go on from there.

Regardless if you are restoring a tractor for general use or just for those main street parades, the gas tank must be carefully & closely inspected. More often than not, the tank is overlooked because it is one of those parts on these machines which are considered a lifetime (?) part & the least of all to give us any kind of a problem. And when there is a problem it is usually isolated to the filler cap being at fault causing problems. On machines that are used very rarely or never, generally have fuel systems & tanks that are subjected to more than the usual wear & tear. That's because the tank is left either empty or possibly partially filled with gas to slowly go bad sitting in the tank & collecting moisture & becoming a chemical biological problem. And while there are fuel additives to stabilize the fuel, they are not intended to be a forever lasting preservative. They to have a limited life span.

When a tank is left empty for long periods of time, the moisture that becomes trapped inside the tank will surely start the oxidation process we all fondly call Rust. And while many say that to avoid the problem, just keep the tank full at all times & avoid the problem because the fuel is a natural barrier to moisture. That is a correct statement to a degree I suppose. But long term storage of fuel in a machine sitting idle for months if not longer creates many other problems for the entire system, not to mention its destruction to carbs, gaskets & engine as well.

Since we are talking about vintage machines here, we will assume that all the tanks involved are of the kind fabricated out of metal, usually galvanized sheet steel. Many of these tanks were fabricated in two sections with a center seam pressed or rolled together in a similar fashion as you would find on many canned foods. While over time the seam could develop a leak, my personal experience has been that the seams in general are quite strong & tight. But the tank bottom itself generally becomes the are of concern since most of all the rust & contaminates are sitting on the bottom. Generally on close inspection through the filler neck, you will be able to see rust spots or light shining through the bottom & possibly sides of the tank. And if you lightly tap & shake a dry tank you can generally dislodge debris & rust flakes which will give you some indication of how sever the problem might be.

In highly corroded tanks, it might just be best to discard the tank completely & try to replace it with an original that hopefully will be in a lot better shape. But if you decide to restore the tank there are definite things you can & should do. First thing is to remove every trace of external paint down to bare metal. And here I give a strong word of caution to all of you who have become addicted to using grinding wheels, orbital sanders & powered wire wheels to do paint & rust removal. Use of power tools can easily & generally does ad to the already damaged tank. Its just too easy to dwell in one location for a second or two on the tanks body & thinning out the already thin metal or puncturing the tank with the edge of a grinding wheel moving at 11,000 rpm. I use nothing at all on my tanks but a moderately sharpened painter's tool & a wire brush. I have found over the years that because these tanks are usually sitting over the full heat of the engines for some thirty years plus, that the paint is so brittle that one only need to look at it intensely & it will crack & peel right off with the least amount of coaxing with a hand tool.

After I have the paint off & down to bare metal, I turn my attention to the inside of the tank. If my visual inspections reveals signs of rust, I generally take a few roofing nails, lock washers or nuts & even better if I have some, small pebbles or ball bearings. I pour these into the tank & then give it a good shaking for as long as my arms will allow. The next step is to pout it all out onto the ground making sure everything is out of the tank. Generally this procedure will dislodge quite a bit of rust & accumulated dirt & you will be able to flush most of it out of the tank on the first try. You may have to do this several times to get most of the dirt & rust out of the tank. In between I use a mix of plain hot water & a strong detergent like Simple Green to clean the tank. I also use my air compressor & blow gun to force dry the inside of the tank. I have found that no matter how careful you are about drying out the tank, there are always droplets left in the tank behind tank baffles or internal supports, & you want to get that moisture out of there.

Once I'm done with the initial internal cleaning, I block off any fuel line connections making them fluid tight. Then I generally use a small amount of kerosene or mineral spirits to roll around inside the tank while I look for any external leaks at the tank seams, or any pin holes. If none are immediately evident, I will let the tank with its contents sit on my work bench over night with a few paper towels under it. In the morning I will take a close inspection for any evidence of leaks. I do this because I have found by experience that sometimes it can take several hours for a leaky seam to become evident or for a fluid to find its way into & out of any microscopic pin holes. If I discover any leaks at all, I start to repair them from the outside. This is where you will appreciate the removal of all that paint & cleaning down to the bare metal. Once I have located the source of the leak, I will apply an epoxy cement like JB Weld to the leak area. On pin holes I will apply the material forcing it into the cavity with slight pressure on the painter's tool. Also I make sure I've built up the material in sufficient quantity so that I will be able to feather it smooth after it cures. And always apply the filler well beyond the area you are sealing. Many of the two part epoxy resins will not make a good bond to painted or contaminated surfaces. Make sure that the epoxy or anything else you use is rated for resistance against fuels that you are using & that all surfaces are sound & cleaned.

Now it's time to turn your attention back to the inside of the tank. There are several brands of internal tank sealants on the market. Much of this material is sold as a complete kit usually containing a cleaning agent to strip away gums & varnishes left behind by bad fuel. Then there is generally a metal etching chemical. You need to "etch the inside of the tank in order to help solidify any major rust areas that you could not clean up & also to th give the inside of the tank a surface texture so that the sealant can grab onto & lock itself down to the metal of the tank. Just think of it as a primer coat. In the event that you have a gas tank that has no signs of rust at all or very light surface rust after you have washed it out & inspected it, you might be able to save yourself some expense. If you have a dedicated paint store in your town or one of the big box home centers, you can get from the paint dept. a small container of Phosphoric metal surface prep & etch. I've used this successfully in combination with my own detergent & cleaning methods & have had no problems. You can eliminate the cost of purchasing an entire kit & limit your purchase to just the actual sealant itself. As a guide to the amount of sealant you will need, generally an eight ounce can of sealer will be enough to coat a six gallon tank or three or four one gallon gas tanks. I say three or four because you will have some loss pouring the material from one tank to another. You can buy sealant from an eight ounce size generally all the way to gallon quantities. But do not buy any more than you need to do the job. The sealants are air activated & as soon as you open the can, be prepared to us it & to throw out any leftover. You will not be able to save any of the leftover material for another job.

Regardless of which you decide to do, either buying a complete kit or individual ingredients, do not try to shorten the process. To do so could only lead to further problems. And if you have a tank that is severely damaged it may require that you cut out sections of the damaged tank & weld in new sections. Generally if this is your situation, it would be well worth trying to find a replacement tank in good shape or one that only requires reasonable repair. You can find the tank sealant kits & supplies by doing a search on line for Tank Sealant. If you are near to a body shop supplier, you may find the sealer there as well or a motorcycle repair shop may have some for you. Two of the more popular brands are KBS & U.S. Tank Sealant. The later is manufactured by the same company that manufacturers POR 15 coatings. This is not an endorsement of either product. There are others out there as well. Do your research before purchasing any product to see what is involved in prep & application as well as cost.

Beyond tank maintenance & repair there is another issue regarding tanks & fuel systems on these vintage tractors. Today, just about any tractor, if not all has a gas tank made out of plastic or other non sparking non conducting material. And they are no longer located over hot engines or adjacent to the battery or other electrical components. I guess back at the start of the riding mower era, we were less likely to blow ourselves up accidently or cause fires by careless procedures. Or was it just design efficiencies that dictated the placement of fuel tanks & the material used to build them. In any case, over the years we have seen the changes that have taken place for one reason or another. But in the long run, nothing works as well as good judgment, common sense & a constant awareness of safety when it comes to repair & restoration & use of the various systems. Never make any modifications to these systems, even if you think Your idea is superior to the original designers intent. Never add into or remove from a system a specific component part or material. There could be hidden dangers in doing so that the users manuals & repair books will not reveal.

Lastly, check with your dealer. Many tractor models, while obsolete have had modifications made to them by the manufacturer. These modifications in many cases are still available as after market kits & are available Free of charge for the asking. I personally know that on model 60 & 70 riding mower there is a battery cover kit. And I recently ordered a primary drive belt for a model 110 tractor & it came with a Free offer for a Battery safety kit as well just for the asking. So check with your dealer or with John Deere Parts directly & get the proper information for your machine. And again, this brief article is not intended to instruct you on how to repair your fuel system or your fuel tank. I leave that entirely up to you. It is however intended to give you something to think about because this is a system that can have severe & tragic consequences if not paid attention to.

Jerry