Hi, so I kept smelling gas even with the carb valve shut off. Sure enough something is leaking at the gas tank sediment bulb. The tank looks fine, inside and out, clean. Painted silver. I am thinking that it is 'just' the sediment bulb threaded junction? It loks like the gas is spread out on the bottom of the tank so maybe it is the socket that the sediment bulb screws into? The lower valve opens and gas comes out if it is opened.
There is a broken off handle sediment bulb valve at the top of the sediment bulb. I never noticed that valve at the top before probably because the handle is broken off. It does not move even with pliers. It is in the perpendicular to the ground position. Is that on or off position?
I am draining the tank now to disassemble it since the valve does not move even with pliers. Any advise is welcome.
First the obvious...time to replace the sediment bulb since it's seized up. Then use Locktite 567 thread sealant when you put the new one in. It's good for gas and oil. Great stuff.
Check the flange on the bottom of the tank too. Mine weeps, so the tank is going to have to come off for repair, as if I don't have enough to do already!
So sediment bulbs are not rebuildable?
Yes, they are, but your valve handle is broken off. Don't know if new handles are available or if they'll fit well in an old sediment bulb.
A new bulb is trouble free, and is a good buy.
You can find another used old one and rebuild it too, most good ones prior to rebuild cost about $15-$25. You can advertise for a used one.
Rebuilding only requires cleaning or soda blasting the bulb interior to rid it of rust, soldering on a new screen, and lapping in the valve and replacing the lead washer and replacing the drain cock if that is missing too.
Ignacio, you can rebuild your bulb - when you have the tank drained and your sediment bulb out, don't twist the handle to try and get it out.
Remove the small cotter pin, washers, and spring from the end of the handle, then use a long 1/4 inch drive socket and a small hammer to knock the handle out of its seat, it will come right out.
Since your handle still has a short stub on it and it is made of brass, you should be able to slip a piece of brass tubing onto the stub and solder it in place to create a new handle.
It can take some force to remove the brass fitting with the screen from the front of the bulb, I clamp the square part of the fitting in my vise and twist the bulb body by hand to get it loose.
If your screen is missing, the vendors sell a replacement that you can solder into place. The vendors also sell the soft lead washer for the fitting.
I cover the tapered part of the handle with toothpaste, then insert the handle into its seat and spin it to lap it in for a good fit. Wash off the old toothpaste and repeat as many times as it takes to get a good fit.
Use this same procedure for the drain valve at the bottom of the bulb.
Once everything is lapped in and cleaned, you can reassemble everything and it will be good as new.
What does 'lapping in the valve' mean? Can I reuse the old lead washer supplemented with aforesaid loctite?
"Lapping the valve" means spinning it in its socket with toothpaste on it. The toothpaste is a very mild abrasive, it will wear the high spots off of the valve and its seat so that they will make a fuel-tight seal.
The old lead washer will likely be destroyed during disassembly. Even if it isn't, it probably won't seal properly and you'll be right back where you started, with a leaky sediment bulb.
The picture you posted sure looks like there is moist-ness on the tank quite a way up from the outlet. It could be something else, of course.
The way to be sure is to have the tank almost full, then take a single ply of a Kleenex and lay it on the tank. If it sticks, and shows wetness, you've got a leak in the tank. It could be a rust hole, in which case it surely isn't the only one, or it could be from damage. Either way, it needs fixing.
Mine was from rust, and the entire inside of the tank showed rust. I didn't want to take chances, since my car lives in an enclosed space, so I bought a new tank. There are potions you can swish around inside the tank that supposedly seal it, but I worried about the effect of modern Ethanol on the stuff, so I decided not to take a chance.
On the sediment bulb, if you're not trying to be period-correct, a much cheaper solution is to go to a tractor supply dealer and get a bulb/valve as used on the Ford Model N tractors. It has a glass sediment bowl so you can see the crud as it builds up, and has the added feature that when you open the valve one turn it takes fuel from about an inch up from the bottom of the tank, but if you run out you can open the valve a couple more turns and it uses the last gallon or so, allowing you to make it home.
Remember that gasoline fumes are heavier than air, so they travel along the floor without being noticed - until the find a pilot light or cigarette or something, and BOOM!! Any kind of leak in your fuel tank is a bigger hazard than you might think.
Most times that large brass nut with screen has been in place for over 80 years and is really stuck! Best results IMO, is to heat the iron bulb with a torch, and get the area around the lever and nut very hot.
Place the hot bulb in a freezer.
Then the cooling of the brass from the iron will let the nut come loose in a vice. The lead washer will be melted away from the heat of the torch, so a new one is necessary, as the old one will be toast or just plain messed up.
Use a small hollow tool or deep socket to push out the lever. Of course the cotter pin and spring will have already been removed for heating.
Lever valve prior to cleaning and then 'lapping' in place in the iron bulb, that will allow the paste compound or toothpaste to give a smooth finish for the taper valve to fit tight, but allow it to move to open or off positions.
After the new screen is soldered to the inside of the nut, fit the new lead washer and then replace the nut tightly.
So I drained the tank into a container but managed to take a gas shower anyway, bleah!
The tank appears to be leaking at the seam of the seat that the bulb goes into. See pictures with red highlight. As always advise on how to seal the tank would be good. The tank inside and out does not appear to be rusted or in poor condition.
The valve handle washer broke when coming off, the spring disintegrated. The valve shaft is bent. See picture. The screen inside is hanging at an angle. I did not get the screen nut off yet. Will try the torch and freezer method. Fortunately or unfortunately the holes appeared to be open so I think I have been getting sufficient gasoline?
Another way of checking for a leak is to drain the fuel, wipe it clean, then spray anti-perspirant on the connections. Put a little fuel back in and you'll notice a wet spot, where or if it's leaking. Easy to tell where the problem is. I keep a a can of ladies, Soft & Dry in my cabinet just for this purpose. Have used this for fuel and oil leaks that were hard to spot. Sure, you'll get a funny look at the grocery store, but the spray works great.
I think you'd be better off at this point to get a new sediment bulb.
As far as the tank leaking, I gave up trying to seal mine an bought a new one. Maybe a radiator/gas tank shop can reseal it for you. Mine weeped in the same spot.
Also, I would recommend whether you get a new valve or a used one you intend to rebuild, that you get some EZ Turn Fuel Lube (see link below). A 5 oz tube will last you a lifetime. I have had different petcocks that have seized up in a short time, this stuff works great when you reassemble the valves. If you get a new sediment bulb, take it apart and put this on the valves.
If the boss on the tank is still solid, and only weeping around the seam at that one spot, then gas tank sealer can work.
Clean the area well, use alcohol to wipe and dry the spot, mix the epoxy 2-part sticks, and apply to the seam. Have used sealer on tank exterior, and it works.
Typical gas tank sealer, auto parts store item
If I do the quick epoxy repair, is there a good way of stress testing it without the gasoline shower again? Fill it with water? I have containers and such for draining gas but inevitably something goes wrong and I get at least a good splash of carcinogenic, neurotoxic gasoline.
Also what is the size thread for the seat if I want to just plug it to test it?
The fitting size is a 1/2" NPT (pipe thread), the plug can be found in brass or steel at your local hardware store in the plumbing section. And yes, it would be best to just buy a plug to test the tank for leaking.
You could fill it with neurostimulating ethanol aged in charred oak barrels, but gasoline would be cheaper.
I have several sediment bowls you can use for parts or repair. Call me.
I have gas tank repair epoxy. I am wondering if it will work upside down? What if I put my shop vac on the fill hole to pull the epoxy in? Trying to avoid taking the tank out.
I have two used oval gas tanks if you can't repair yours. Call me.
They are not hard to take out and replace.
To seal the bulb threads I'd recommend this product. http://www.aircraftspruce.com/catalog/cspages/ezturnlube.php?clickkey=218206 Dan Hatch turned me onto this product and it works great.
DON't put your shop vac on it!! You could collapse the tank. It's amazing how easy that would be.
The epoxy sealers will work in any attitude. It's like a paste, and you smush it into and around the hole by hand.
Which brings up a point -- I like to have a box of rubber gloves in the shop. I use the ones they sell at the auto parts store, but the ones you swipe from your doctor's office work as well. Instead of laborious hand cleaning, I just strip it off & throw it into the can. (Trash can, that is)
I will also add that using a vacuum on the tank will probably cause a explosion when the fumes hit the spark of the brushes of the motor
I used the putty-type gas tank sealer from O'Reilly's. Thought that worked, it didn't. Leaking again from the same spot around the flange except that now it has tank sealer over it. :-(
Must be the type of crack in the tank metal or the flange, for if you fully cleaned and wire brushed the area to bare metal, especially in the open seam, and used lacquer thinner to dry off gas, then the putty should have worked.
Here is spot of a pin hole leak, cleaned well to remove paint over the spot to get to bare metal, and smothered that pin hole with putty, has been good for two years. The matt look to the paint isn't gas, its from the lacquer thinner used to clean prior and it changed the finish look, the areas around and the putty itself are completely dry.
It's a boy! Removed the tank today, going to take it to a radiator shop tomorrow. Seems like a hairline crack around the flange or maybe a pinhole. I think I will do lock washers on re-install. Those cotters are in a tight place.
My round tank had a flange problem. I took it to a local radiator shop, and they did a super job on it. Cost me $80, and it was well worth it. The one on my touring is weeping now, and I may just try Dan's method for the time being, because the whole body has to come up to get the gas tank out!
$35 radiator shop fixed it. My theory is that someone in the past torqued the sediment bulb too hard on the flange and hairline cracked it around the perimeter. My repair probably didn't work because even though I did not torque it very hard it was already weak so my gas tank repair patch didn't hold and probably cracked again. If I were to do it again I would have installed the sediment bulb first, then put the gas tank patch repair on.