View Full Version : Gas tank flush

01-19-2005, 05:14 PM
Somewhere in the first 2 feet of fuel line from the gas tank I've got a serious blockage on my TR3 that's been dragged around the country on trailers for years. This weekend I'm going to pull out the gas tank and see what kind of gunk I have growing in there (no I didn't drain anything when I stopped driving it... I know....)

I seem to recall Moss or someone selling a fuel tank flush kit that would clean out the rust and then there was some sort of sealer that coated the inside.

Does anyone have any experience with this or have any recomendations?

01-19-2005, 06:38 PM

I've not yet used a tank cleaner/sealer myself, but am seriously considering it for both my TR4 and a motorcycle. The cycle especially needs it since it sat for many years before I bought it and developed some spot rust in the tank. Just enough of that sheds regularly to get into the carbs and plug the jets. I've cleaned them far too often! A fine fuel filter helped, but the problem still persists.

I know the TR4 tank was repaired after an accident. The side mounting bracket poked a nice hole in the tank, lucky it was less than half full so it didn't dump a bunch of fuel in the car and on the ground, and the car didn't go up in flames! I imagine the process of brazing or welding that repair has accelerated corrosion within the tank.

I've looked into the pluses and minuses of the tank cleaning/sealing process. What I've found is that, yes, it works. You first put a cleaner in the tank and slosh it around, let it do it's thing neutralizing rust, etc. Then an etching preparation is put in and sloshed, to ready the tank surface for the sealing coat. Finally the sealer is put in last and sloshed around to try to cover all internal surfaces.

Done right, I understand it works well, at least for a while. It's critical that each step be done properly and thoroughly.

I have heard several reports of the sealer starting to peel and causing system blockages itself, after 5 or more years. However, I don't know if that's due to poor application, or is in any way typical. I hope some others jump in here and tell us!

At least, it sounds like it's possible to buy 5 more years' use out of a tank before having to replace it. Whatever is used to seal has to resist all the detergents, alcohols, etc. put into modern gasoline.

Yes, the big TR vendors sell kits. But, almost any restoration specialist offers it, such as www.eastwoodcompany.com (https://www.eastwoodcompany.com) or www.por15.com. (https://www.por15.com.) I'll shop around, there are probably many online sources.



01-19-2005, 06:54 PM
I speak from great experience that if not done properly, a poorly-sealed gas tank can be a real pain. My '59 TR3 would intermittently stall, sometimes in really dangerous places (I once was out to lunch with my team at work, and one of the ladies that worked for me helped me push the car through one of Houston's busiest intersections.)

It turned-out that the gas tank had been sealed, and the sealant was peeling off and kept clogging the line/pump. It burned out the pump when the guy I sold it to tried to drive it from Houston to NC. (I told him it had a fuel-delivery issue, and told him to bring a new pump with him, which he didn't.)

So I would seriously consider just buying a new tank for the thing. Not cheap, but much easier to deal with, and a long-term solution given the nasty quality of modern fuels.

01-19-2005, 07:03 PM
I have used the sealer on all my cars and a couple of friends with no problems other than the one guy who put the tank back in before the final sealer set up and his sending unit stuck in the sealer. It will fill all the small holes you will get when you sand the outside, so don't paint the outside until you have completed the inside. I can't remember the name off hand but got it at a motorcycle shop.

01-19-2005, 07:27 PM
An old trick for cleaning out a rusty gas tank is to pull the tank, wash it out completely with water then drop about a foot or so length of heavy chain inside. Roll this around inside the tank till your arms can't stand it anymore then let your neighbor do it for awhile. Really cleans out the rust. Finish with the sealer, etc. of your choice. It works good.


01-19-2005, 07:58 PM
Done a bunch of them, all came out great. Dont use a slosh, for the reasons given. Spend some money and have it boiled out,or spend less and do it yourself. Wash out many times with strong detergent, hot water, flush with hose.You must do the soap step first to make this work.Buy a gal of muratic acid pour in tank add water,cover, let sit for days. It wiil dissolve all rust but not the good metal, flush with baking soda and water alot.Dry with a hair dryer,bone dry. If any holes develope,sand and seal with fiber glass resin and mat on the outside. sand smooth and paint. This is the basic outline. It lasts forever with nothing on the inside to plug up the system Muratic acid will not cut petroleum, thats why you must wash first

01-20-2005, 01:44 AM
I've been thinking about this, too, since my tank has some (ok, quite a bit of) surface rust. I've seen the slosh/sealer product online, and the muratic acid process also sounds interesting. I'm curious though, with either process, how to handle the leftover fluids. Are they toxic, can they be washed down the driveway, do they need to be collected, etc.?

01-20-2005, 01:28 PM
Full-strength Muratic acid is used to etch concrete when laying aggregate pebbly-looking sidewalks around pools and whatnot. So I wouldn't be running it down your driveway.... of course the final flushings after the long soak wouldn't be strong enough to cause any damage. But you might stain your driveway.

But then again if you own a British car then your driveway is stained anyway... it might actually turn out cleaner.


Simon TR4a
01-21-2005, 12:26 PM
If anyone is interested I have a good used gas tank from a TR4a, (fits TR6 too, I imagine), which would be a lot less work.

01-21-2005, 02:25 PM
When I pulled my Spitfire tank, it had a brown surface on the indside that I took to be rust. Turned out it was dried gasoline residue. I tried to get a ra shopa and tanker truck cleaning business to boil it out and no body would touch it. I used a couple of solvents, one being mek. It cleaned the tank right up. I also used small steel shot that a neighbor friend gave me and blasted it through the sender openening. I used one of the sealers that is said to be alcohol proof and have had no problems after several years.

01-24-2005, 01:20 PM
Thanks for all your suggestions! I pulled the tank out this weekend and surprisingly enough it was completely clean. Not a bit of residue or rust. The fuel I drained didn't have a single bit of junk in it and water came out clean. And I was all ready to play with muratic acid....I had even scrounged up a length of chain to shake around in there.

I found that the fuel line leaving the tank was completely clogged where it bends to go up over the axle. A little poking with baling wire revealed a bunch of red paint flecks. Apparently the dreaded previous vehicle owner (who's name I haven't cursed in years) had managed to paint the INSIDE of the fuel filler pipe. Grrrrrrr. But that explains a lot. (like why it started sputtering like mad when I tried driving it onto the trailer when I was moving from Portland in 1997 and why it would run great until I got 2 or 3 blocks from the house)

So now I just need to repaint the tank while I have it out and get it all back together. Hopefully this Saturday I'll actually get her to start again and then I can tackle the brakes.

I can't wait to see the look on my kid's faces when they finally get to actually RIDE in daddy's car instead of just sitting in it and pretending.

01-29-2005, 11:52 PM
My "50 TD had been sitting for almost 20 years. Towed all over the country. Last spring began restoration and shocked to find the gas tank dry with 3/4 inch black residue. It was very difficult to remnove the dip stick. I send the tank to an outfit in upper New York state near Utica. They cooked it and coated the in side. About $160. Like new. I expect I will have to change all the lines. Will lookfor the outfit if you are interested.