Leaking Fuel Tank

[JeffMoore64]

Evening Gents,

So in my excitement to get out and put a few miles on the TC, I filled the tank with gas and was ready ready to play... Imagine my woe when I went out to the garage and noticed a small 10" circle of gas on the cardboard I thoughtfully placed under the tank. My father, who has since passed, owned the car prior to me and I seem to remember him saying something about having had the fuel tank repaired 10 years ago. Looks like I have a new leak or the old gas/water from when it sat has eaten a new hole. The way I see it I have three options in cost descending order:

New tank from Moss = $1000

Braise the old tank = $unknown and will probably leak again

Use something like RED-KOTE® to seal the tank from the inside out = $40

I'm leaning toward the latter option due to ost and the idea that sealing it from the inside is going to be the only way to solve this permanently without replacing the tank.

The RED-KOTE® website talks like their product really works. Has anyone ever used this stuff or some other product that works better?

Thanks for the replies,

Jeff

[Steve Simmons]

My experienced with sealed tanks has been less than positive. I have an original early MGB tank that will get thrown away because the liner separated. I would repair the holes, or if the bottom is thin, perhaps cut the bottom out and weld in a new piece. Just my opinion though...

[cdrolshagen]

Hi Jeff,
you have just one choice - a new fuel tank.
I bought one few weeks ago - from Michael Breakhouse
http://www.sportscarmetalworks.com/t-type-price-list/
He make these tanks for MOSS and other dealer as well.
I think he ship around the world,
cheers Carl

[JeffMoore64]

Thanks for the link Carl. The prices are certainly more reasonable than Moss's.

However, I'm inclined to try a sealer first before popping for a new tank.

I haven't removed the tank yet so don't really know what the condition is. The fact that the ends have a flange leads me to believe that they must have been braised originally.

Any other folks have thoughts to add?

Jeff

[Duncan M]

Another one to look into is Caswell, which is a 2-part special epoxy. Makes some heat as it dries. I used it on an original TC tank with surface rust (inside) from sitting, but no leaks. I rinsed it with lacquer thinner as per the directions. I would think this might work better for pinhole type leaks. After mixing the 2 parts it is thick but pourable at first (work fast) then dries in a thicker layer (I would think) than other sealers.
http://www.caswellplating.com/epoxy-gas ... ealer.html

The other one you hear about is POR 15, and is basically a urethane paint you slosh on after using the makers prep kit for gas tanks.
https://www.youtube.com/watch?v=OMxCWNUHNoU

[cdrolshagen]

Hi Jeff,
I have two TCs, both have had the same leaking problems - one leak at the bottum of the sides, cooroded from inside,
and the other leaks att he bottum, where the brackets are welded to the base of the tank.
Tanks are originally welded and not braised.
cheers Carl

[Tom Lange, MGT Repair]

I agree that tanks do rust out at the bottom, especially when they have sat for a while. But don't lose sight of the fact that the leak could be coming from the fuel-sender, where the gasket is notoriously poor. The best gasket to use as a replacement is the double-flanged rubber one sold by Doug Pelton at From the Frame Up (see his terrifically-useful page). Be cautious replacing the mounting screws with Moss pieces, which have the wrong thread, and which WILL cause a leak!

Pulling the tank is not that hard, and gives you the opportunity to both remove the accumulated junk from the bottom of the tank, give you a chance to look inside and see the condition of the metal, and also to be sure where the leak(s) is/are.

One solution is to throw money at this problem, but replacing the tank may not be necessary.

Tom Lange
MGT Repair

[stephen stierman]

Before you throw a tank away and spend big bucks for a new one, determine where it is leaking as suggested. Most of the time they aren't rusted out at the bottom; the sender is leaking, a seam is leaking, or the spot welded feet may have finally fatigued and are seeping. A good radiator shop can fix them.

[Richard Withington]

I suggest you look very carefully at new tank from the supplier mentioned. I had a supposedly new tank which proved to be a nightmare, it was rusting inside which caused endless problems with contaminated fuel.
Not sure whether it was rusting metal when it was made or old stock which had been standing but it was impossible to remove the rust and had to replace with a tank from another source.

[Marv]

Well, if you're going to get a brand new tank, you may as well cough up the few extra Benjamins' and get the stainless tank from Doug Pelton. No rust ever, then you can worry about something else!!!!

Marv TC5141

[JeffMoore64]

While we're talking about the fuel tank. The image below is I believe the "sender unit". I wondering how this is connected to the rest of the car as there are no wires coming out of it. My TC also does not have a Low Fuel Light so is this sender unit even used or needed? If I decide to line the tank, and this unit is not in use then I'll just leave it in. Otherwise I'll need to pull it and figure out it's use.

Jeff

[Duncan M]

Jeff, the warning light is to be located to the right of the tach, at about clock level. The sending unit has no wires coming out, but does have a threaded post inside a protective "cup" (yours are currently missing) where a wire attaches, and is held down by a plastic sort of knob similar to the elect. connection on the SU fuel pump. Here is a pic of the unit I lifted from here:
http://ttypes.org/ttt2/mg-td-fuel-tank-sensor-leak A good read.
Doug Pelton (FromTheFrameUp) sells a special gasket #GA320
The original sender has 3 screws holding down the top plate, as yours. Replacements available have 4 screws? The warning light is a special unit, as it drops down current from 12V and goes to the sending unit, where the contacts inside it meet (when fuel level is low) always drowned in petrol. A somewhat complicated British circuit to envision and troubleshoot, until you understand it. The low voltage light bulb in the dash no doubt confused more than a few people. It uses a 2.5V .5amp bulb, same as the ignition warning light.
http://ttypes.org/ttt2/one-of-lifes-little-mysteries

fuelsensor4.jpg (40.25 KiB) Viewed 7326 times

[frenchblatter]

The main reson for leaking sender units is the screws are overtightened. I have a tech tip on my TC blog.

However, just nip the 6 screws up, if you tighten them too much the flange distorts and then leaks.

See: http://www.lotus7news.co.uk/MG-TC-MAY16 ... l%20sender

[JeffMoore64]

Ah ha! So somewhere in the car's past the dash must have been redone. I don't have the map light or the fuel warning lamps but I can feel where there is a hole under the black dash vinyl where both should be. Once I removed the sender unit I found it to be frozen in the up position. No matter, I'll just put the sender back in the tank as I have no intention of fixing it at this time. Will probably just use a little fuel safe silicon sealant in place of the cork gasket too.

Thanks again all for the advice.

Jeff