Draining bad gas...

So I finally got the truck to fire... after replacing ALL the ignition components. Now I need to drop the tank and drain the bad gas and flush the lines... I was wondering if anyone had any experience with this and the easiest way to do it. Also anyone have any experience with the stuff you can use to reseal the tank, I was told to use this stuff as well...

I had to do this recently on my diesel truck. Get one of those siphon pumps to get as much out as you can, and let the rest evaporate. My fuel sock was clogged, I would change that while you have the tank pulled.

Is your tank actually leaking? If not I wouldn't mess with those sealers, I've seen to many horror stories.

You probably need to check for rust and go from there.

I had to drop the tank on my 86 B2000 to replace a faulty sending unit. I'm not sure about your truck but mine had a drain plug in the bottom of the tank that made draining it pretty easy. You may want to check yours to see if it has one as well.

Also, I'd pick up a new or good used tank before trying to use the liquid liner. That stuff can break loose and cause all kinds of clogging problems if your tank prep isn't A+.

I just recently dropped and cleaned my tank due to rust clogs. See:

Some suggest removing the bed (6 bolts) versus trying to drop the tank. I started this route, but decided against it due to the bolts being extremely rusty and I needed to have the truck running. If you can remove the bed, it would make it a lot easier to access the filler neck clamp as well as the fuel lines.

While yours may be completely differently, on my '87 B2200 carb-ed, there are four bolts total for the tank. The front two are stationary, whereas the rear two require a wrench on the top (12mm wrench). Each bolt has two nuts, a 12mm and a 14mm. The filler neck also has four small bolts, 8mm. I do not suggest trying to use the Philips head but instead utilize the hex head. There was (not anymore ) some adhesive and rubber strips between the mounts (on the truck) and the fuel tank. I had to pry the tank loose from this the first time I dropped it. I would suggest replacing the rubber strips if they are damaged during removal, but I don't believe the adhesive is a requirement.

There are four gas lines as well as the electrical connector. The front two gas lines are for the fuel pump and return line (which I capped since I am not using the stock fuel pump). The rear two lines are for the charcoal canister I believe. The hoses are stiff yet brittle from so much abuse, age, and fuel eating at them. If you have the money, I'd suggest replacing them to eliminate future leak issues. If you do, watch the sizes. They're nearly all different sizes.

For flushing the lines, you could simply blow them out once they are disconnected both at the tank and the pump. Just use an air compressor if available.

I know it's a bad idea, but there was so much rust in my tank, I used the water hose with a lot of pressure to knock everything loose. If you take this route as I did, MAKE SURE ALL WATER IS GONE. The water will tend to accumulate around the rust. I let my tank sit for a day propped up to let the water drain. The first few fill ups you will need to use some gasline antifreeze to remove any drops of water that may remain.

As stated above, check your fuel sock. It's probably a good idea to replace it since you already have access to the tank. Use some sandpaper on your fuel sending unit to remove any rust from it as well.

Even after cleaning the tank, little microscopic specks of rust remained. (I must've not done a thorough enough job.) I have kept an extra fuel filter on hand because the first couple fill-ups of the tank would clog one with rust.

I read the title and was thinking that the easiest way to clear a tank is with a rag and torch.

For a serious answer, just get a new tank. They can be special ordered at many part stores, I got one a few years back for $100. 4 bolts to get the tank down, 6 screws to take the filler neck out, and a couple hose clamps to get out of the way.

While you are there also replace the fuel filer hose and any other rubber, odds are that your original rubber is deteriorated and brittle. Also replace the screws of he sending unit with bolts of the same thread, it will make any future R&R a lot easier.