Here are some pictures...





I replaced a rear marker light on the driver's side and noticed a strong gas smell-so i checked it out. It appears that i am leaking gasoline from my gas tank down a mounting bracket on to my driver's side muffler.

Suggestions as to a fix please ?

This would also explain my crappy gas mileage lol

 

Well, Its pretty obviously leaking. Not uncommon. Will probably require a new tank.

 

You might not have a bad tank. Check the rubber hoses going to the tank.

Not sure about the 72 as to whether the fuel lines are on the bottom or the top of the tank. If they are on the top you will have to drop the tank no matter what....

The fuel lines run along the inside frame on the passenger side, they are stainless steel. From there the fuel lines are rubber both on the fuel pump side and the tank end and they will crack and leak eventually... My 77 line was leaking fuel onto the muffler when I first got it...

Start with your fuel pump. If you have 2 lines connected one is from the tank and one is an overflow back to the tank. Some people cap the return line to the tank. On the driver side you will have a line for the vent.

If your leak looks like it is coming from the passenger side of the tank it is most likely the line to the fuel pump.

Good Luck

Rd

 

Hi MWW,
Since you show the leak/stain on the driver's side of the tank it makes me think you may have a vapor line problem. This is the line that runs from the tank along the driver's side frame rail to the vapor cannister behind the driver's side inner fender.
These are the connections at the tank and the long line on the frame rail.
Regards,
Alan

 

Check out what Alan 71 suggested. If that is not the problem look for small rust pin holes under the bracket area.

Mine had the same leak pattern as yours and it ended up being pin holes that started to leak more and more like yours. I ended up replacing the tank, hoses, valve and everthing else since I was in there. Easy job and it will give you some Peace of mind.

I ordered everthing from Quanta with no problems: http://www.quantaproducts.com

 

I think BP may be right. After I looked at the pictures again it looks like the leak may be somwhere else but you're seeing the result of it on the end of the tank support.
Regards,
Alan

 

what is the best procedure for removing the gas tank ? My ASM shows the diagram but.. not a step process. How should i drain the gas from the tank? I will start removing the stuff this week and i'll report back on my findings.

 

I am sure you can find something detailed on the forum if you search for it.

Both Alan and BP are right, your leak could be anything. You will soon find out.

Best to my recollection here is what you have to do.

Remove as much gas as you can from the tank. This is more for weight than anything. The tank removal is easier than the tank replacement at least from my experience. You want it empty.

The tank is an aluminum giant beer can. Theoretically you should not have to worry about sparking the tank against the frame and blowing yourself up. You could however, hit your wrench against the frame and create a spark. You might want to rig up a fan under the car in a well ventilated area to dry up all the excess gasoline lingering around before you start. Of course the fan can spark too so I said well ventilated.... Murphy's law applies here. Do what you got to do to be safe. Also, keep your gas cap on since you have most of the vapors inside the tank.

Remove or pull the little booty around the filler cap. Different years have different booties. You just don't want it hanging on while your pulling the tank.

You want the car raised in the air on jack stands. Make not and reference how the tank is sitting in place. You want it exactly back in place where it is sitting now.

Drop the exhaust mufflers. Mine broke right off in my hand. If your exhaust is original you might find the same.....you might not.

Remove the spare tire and the carrier. Once you pull the tire out you will see. You will have 2 or 3 bolts in the middle, and two carriage bolts that allow the carrier lid to swing. Some PB blaster and a good pair of vise grips may come in handy.

Check out Alan's pictures. You will have the one fuel rail on the drivers side, and two on the passenger side. These lines come off the frame just as the pictures show behind the wheel resting on the frame. Feel for the rubber hoses and cut them. If the car has been running you may have some spillage. Be careful.

Note - Now is also a good time to order the rubber hoses for your fuel pump as well. If your hoses are rotting on the fuel tanks side, the pump ones will be as questionable as well. The one fuel pump hose has a weird kink in it so you might want to consider ordering one from anywhere. The return line can be replaced with normal Auto Zone fuel line.

The straps on the tank are attached to the crossmember under the tank and attached to the rear of the car's frame with two bolts. Loosen the two bolts but do not take them out. Most of the time you can keep the straps in place. Loosen the crossmember and remove it from the straps.

Pull the tank out.

The straps have rubber on them to keep from cutting into the tank. Inspect them for wear or damage. If they are damaged you might want to replace. You can use any kind of rubber you want but mind the thickness. You want the tank to bolt exactly up in the same place it was.

Find your leak....... Replace all the rubber hoses

Reinstall in reverse order....

This is the best recollection from memory......

Good luck and feel free to ping me back if you have any questions.

Rd

 

The tanks in my 68 and 70 were tin plated steel. The duplicate tanks from Quanta were also tin plated steel. (I think it was tin.)

The tank in my 70 was worse. It had small pin holes. When I re-install a new tank, I wash it with lacquer thinner first. The new tanks have a slight paraffin like coating on them which is a lubricant for the pressing process during manufacture. I painted my tanks with Eastwoods Tank Tone paint.

To get gasoline out of the tank, after draining it, pour in alcohol. Alcohol will dissolve the gasoline, and then rinse out the alcohol/gasoline mixture with water. If there's still some fumes, I suggest dropping in a big chunk of dry ice and putting the gas cap back on - loose - Do this say, the night before. The dry ice will fill the tank with CO2. With no oxygen, no worry about an explosion.

 

Hi MWW,
Here are a couple more pictures showing the passenger's side of the tank.
The smaller line that goes to the nipple on the side of the tank is the fuel return line.
The larger line is the supply line that goes under the tank to the fuel sending unit mounted in the bottom of the tank. That's the line that will probably be full of gas. Be careful.
Regards,
Alan

 

so i began to tackle this problem this weekend.. how do i get the blasted spare tire off?

my leak is right above the spare tire carriage. i can feel it with my hand, and i found some cut wires going from the key cylinder and a cut wire coming from underneath the gas tank.

Ill get pictures of it tomorrow when there is more light in the garage.

 

I documented my gas tank swapathon in threads you can find in the archives. (search on my username + gas tank) I had to learn everything step by step the hard way, because that is my nature. First I learned that gas tastes horrible as I tried to syphon the gas out of my tank! I only needed to remove one side of my dual exhaust to drop the tank. I remember the spare tire carrier (your current problem) being a PIA to get off. You have to unscrew some bigass bolts as I recall... keep at it, keep asking questions. Don't blow yourself up!!!

I had to loosen the gastank support brackets and slide the tank slightly before I could see the obvious source of my leak. I believe it is fairly common to get leaks directly behind the brackets due to rubbing.