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MG MGA - gas tank/sender issue - '57 1500

Got the floorboards/seats in and the engine in - engine even turns over with the starter - really cool! Carbs will need to come back off and be gone through with a new carb kit as some of the rubber is not in good shape. Seat covers are trash, but I'm going to wait until after the body work is done and I start on the interior to recover the seats so I don't have to worry about these. I ran the fuel lines and wiring from front to back, and ran about six extra wires just 'cause (more on that below). But I digress...

The next project is to put the gas tank back in. The tank was Kreemed (or similar) a long time ago and the lining is failing all over in Pringle potato chip like crispy flakes and pieces inside. Unfortunately, some of the pieces are hard to knock loose - and of course most of the inside of the tank is inaccessible to tools. I took one of the flakes and dissolved it in MEK - it turned back into a gooey mess. MEK was the solvent for the stuff I used to use on motorcycle tanks, and seems to be the same for this stuff.

What if I dump a whole quart of MEK into the tank and let it rest on each one of the sides for a while to resoften the stuff - would it re-adhere or possibly turn into glue soup which I could then at least drain out - or some of both perhaps...? Worth a shot?

What about filling the tank with soapy water and nuts and bolts to slosh it around and get out whatever loose stuff there is? I am afraid if I use the wrong size hardware it will itself get stuck.

Anyone "been there done that"? What advice do you have?

On the wiring - the sending unit only has one wire going to it, and I am guessing that is the positive wire, and I'll need to run a ring to one of the screws to ground the tank. Also, the fuel pump has a hot lead and a grounding ring that I am guessing goes to one of the mounting screws. Would it be better to take one of my extra wires and tie both of these to a ground lead that goes the grounding terminal block that I plan to install? I ran a heavier gauge green lead from the negative battery terminal all the way to the front to allow myself to ground the dash lights, etc. so I don't have to depend on the return path through the dashboard and all the fasteners, etc.

Want to do this stuff while I can still get to everything - body is off and the floor boards haven't been screwed down, etc.

Thanks.

JIM in NH
AJ Mail

2nd question. I just rehabbed the fuel sending unit and made a new "hot" wire and ring terminal connection for the lead that goes to the bottom. Old one was cut.

There is a green wire with a ring terminal on the harness at around that location - is this the the wire that should go to the screw on the outside (one of the six fixing screws) of the sending unit body? I didn't think any of the wires in the harness were to ground and assumed I'd be grounding it to the frame (or fuel pump mounting point). Is this an anomaly as a result of switching to negative ground?
AJ Mail

JIM,

I had a tank that I "sealed" in '91 with a sealer that was NOT ethanol resistant. The '08 10% Ethanol fuel in other states loosened it in big sheets and clogged the fuel intake and pump screen. I could find no solvent that would disolve it enough to be sure that it all came out the drain. (See image of some of the stuff)

It was suggested that having it cleaned by a machine shop might do it or maybe a radiator shop. I decided that because of the baffles, limited drains, etc. in the tank I would question if I could ever confidently get it out for less than the cost of a new tank. Even the maker of the sealer (POR 15) recommended a couple gallons of their tank cleaner followed by repeated treatment and flushing MIGHT get it out. Again, cost more than the new tank. I couldn't find a solvent that would do more that soften the stuff. You might get lucky and dissolve it but you will never know for sure if you got it all. I didn't want to find out sitting on the side of the road in a storm at night--and hear my Wife discuss the situation.

I drove the car with the "sealed" tank for 6,000 miles before that one tank of 10% ethanol did me in within 150 miles. After fighting it for a year and over 2,500 miles of trying to clean it out I finally got a new tank.

Just my $0.02

Jim


Jim Ferguson

AJ
Green wires are fused ign controlled power; there should not be one at the back of the car. It should be Green/Black for the sending unit, and there's no other similar wire in the area. White for fuel pump power. In Lucas, Ground is ALWAYS BLACK! Don't run any other colour for ground!

FRM
FR Millmore

Jim,

I tried to resurrect my gas tank but ended up buying a new tank. I used a couple of short lengths of chain to knock off the loose pieces. In my case that was rust, a lot of rust. The tank had been sitting for years half full of gas and as a result the upper half of the tank was a rust bucket. After knocking out the big chunks, I took it to a radiator shop to have it boiled out and lined. Big mistake, not only did the shop not line the tank with the proper material (it dissolved and disappeared) but they also painted right over the exterior rust. This past year a whole series of pin hole leaks appeared in a line above the sending unit. I managed to keep ‘em plugged up with epoxy through the summer. I spend a whole lot of time and over $150 to try to save the tank. So in the end my new Moss tank cost me over $400 ($150 down the rat hole and $250 for the new tank).

If there is any question as to the integrity of the tank, go for a replacement. My 2 cents.

John
jjb Backman

OK then, if I am going to end up getting a new tank, it is worth a shot at cleaning this one - I will put some chain lengths and into the tank and let it knock around for a while to get out what I can of the loose flaky stuff, and then let the MEK work on the rest. My tank has been stored since '04 bone dry with no gas in it at all - and rust doesn't seem to be an issue. If I find any falling out with the chain, I'll run some Muriatic Acid in it before the MEK treatment.

As long as I don't plan to pay a radiator shop, I have nothing (not much) to lose...

To clarify - the green wire (poss. with black stripe -I'll go check) with the ring terminal next to the tank sender on the harness is the "hot" wire for the sender, which should be connected to the threaded stud on the bottom of the sending unit - and a black ground should be rigged to one of the other six bolts.
AJ Mail

AJ-
Right. Green feeds the gauge and is true fused power. The G/B wire is "Hot", but it's not a power wire, as it has passed through the gauge at this point, so it's actually the ground for the gauge works, which is why it has a Black stripe. Once it passes through the variable resistance sender, it comes out as a true ground, hence Black.

FRM
FR Millmore

AJ,
Someone sealed it for a reason. I'd get a new one. Mine was quite rusty. I added gravel and detergent and set it up with a fixture to "tumble" for a few hours at about 15 RPM. Got rid of the rust but I emptied a bit of stone dust from the fuel pump strainer after the first few thousand miles. I don't think this would have delt with old sealer however.


D Sjostrom

The fuel tank sending unit is grounded through the fuel line. The fuel line is grounded through the fuel pump ground wire. The fuel pump ground wire is a short (less than a foot) black wire that attaches to the frame and the fuel pump body. This short wire is not part of the wiring harness.

New gas tanks are relatively inexpensive (less than $250 if my memory serves) from Moss and their distributors.

Good luck
Don Carlberg
Don Carlberg

Don is correct, no need to ground the sending unit for this reason
David werblow

Well unless somebody has cut the pipe and fitted a hose section, or the pump lead is dodgy, or a lot of sealant has been used on the sender, or any number of other reasons why every single electrical device should have a discrete and definite ground.

FRM
FR Millmore

Muriatic acid is simply a commercial grade of HCl. In concentrated form, it will destroy your tank and generate toxic fumes, including chlorine gas, when it reacts with the iron in the steel tank.

Radiator shops "boil" out tanks with hot caustic (KOH or NaOH). The same solution is often used for engine blocks as a degreaser. Except for a few limited applications [some body solder fluxes, phosphoric acid for some surface rust removal applications, and radiator flush (oxalyic acid)come to mind], I can't think of anything on an automobile that would benefit from contact with acids in general, and concentrated HCl, in particular.

Steve

Steve Brandt

I use muriatic acid to sharpen files, clean rusty nuts and bolts, and derusting of other parts that don't clean up easily on the wire whee. The "safe" acid that Home Depot sells is a dumbed down version (less concentrated) of the stuff you can get at the plumbing store, but works very well for stuff around the garage. It derusts gas tanks very well, but you have to make sure you oil or coat the surface quickly after that or it will flash off again with rust once it dries.

JIM
AJ Mail

Hi Jim,

I purchased a gas tank from Jaguar by Jorge on eBay a while ago.

It's heavier gauge than others. I've had no problems with it. It currently is going for $ 225. with free shipping.

The only problem I see in trying to salvage your old tank is how thick is the remaining steel.

Cheers,

Larry
York, Maine
L. Mazoway

This thread was discussed between 08/11/2009 and 10/11/2009

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