drained the tank in my '64 F100 yesterday to get rid of old fuel. also installed a new sending unit while in there. ran great until I took it out on the road, then started stumbling and eventually died. isolated problem to fuel flow from the tank, as in, there is almost none. I can blow air down the tube, but seems restricted. question: does the siphon tube have any kind of filter or screen on the end of it that might be clogged? or is it just a stright piece of pipe? TIA - Paul

 

took a chance and ran a coat hanger down the siphon tube and found two spots with definite blockage of some kind. rodded it out and all is well for now. pretty sure i'll be pulling the tank to have it boiled out in the near future, though...

 

Glad we were here for you and were able to help.

John

 

no worries, you guys haave "been there" for me on several occasions. siphon tube clogged up again this morning as I pulled into the parking lot at work. guess I'll be pulling the tank this weekend.

 

poboy, Have you removed the tank from the truck. I suggest that since you have rodded the line, you pull the tank and rinse it with new gas and see if you can pour any matter out of the filler neck. If it stopped up that fast there must be something in there that needs to be gotten out.

Once it's rinsed well, you shouldn't have any more problems.

good luck

John

 

When I cleaned my tank out, I used a sealer on the sending unit that was not gasoline compatible. It swelled up and dropped blobs of goop to the bottom of the tank, and did a great job of plugging the siphon tube. Nothing like pulling the tank a second time.

Dave

 

I haven't pulled the tank yet, just through pure laziness. Though given the amount of time I have wasted trying to avoid pulling it, I could have done so several times over. how's that for smart?

Paul

 

Hehe! Join the club!

To clean out a tank a lot of people use a bunch of old screws and nuts mixed with water and detergent. Agitate the tank, turn it over and over, -anything to let the assorted hardware scour out the tank. Do that a couple times, empty the junk out, flush with water and allow to dry. Flush with alcohol and allow to dry. Then get some gas tank coating sold as kits in auto supply stores and coat the inside of the tank to prevent future corrosion problems. Follow the manufacturers directions.

Just use a little thin film of silicone dielectric grease on the seal rings and hoses. Remember the seal ring is a SEAL, no sealant needed! If it is old and hard replace it. Gaskets are the same, they are the seal, no sealant needed. The silicone grease is just to help it release and not stick the next time you pull it apart.

 

Eric, There have been several of us that have found that new gas works as well, and there is nothing but fuel to be concerned about left in the tank.

Not saying your method wont work.

John

 

We have discussed this a few times around here. It gets to be a trade off between getting a new fuel tank and all the time and effort of reconditioning an old one. A new tank is usually best if they can be purchased.

 

In general, I would agree.

And there are repro tanks available, which appear to be good quality, at least the one I got from LMC was.

I *have* had more trouble with a leak at the fuel line connection at the top of new tank, though much less trouble with rust in my filter.

In my case, the fuel line connection may be more of my own doing -- I wanted stainless, which is notorious for being less malleable and more "leaky" than good old steel.

 

Mainly I was just elaborating on John's post about cleaning the crap out of a gas tank. If someone goes to all that trouble to pull the tank and try to flush it out they might as well do it right. Try to get the stuff out that will be falling off soon and not just some of the already loose stuff. -Then protect their work.