[ftwmlp]

My car has been setting for several years now with a small (unknown) amount of gas. In preparation for re-installing the engine, I would like to drain the tank of the old gas and replace with fresh. The shop manual has a diagram for making a siphon hose, but the measurements appear to be in conflict to my unskilled eye (see attached). Has anyone made a similar arrangement and if so, to what measurements? Thanks for any help.

[pjw1967]

I would take out the tank and have it cleaned and coated. When my '67 was rebuilt in the early '90's, the guys who did left the tank out for awhile. The inside of the top must have rusted. They put the tank back in, and put some gas in it. After I bought it, I took it out for a run and stopped to fill it. Within a few miles, the full tank of gas had scoured some of the rust off the top, fouled both fuel filters, and got into the carb. Had to remove the tank to get it cleaned, and got it coated as well. Got a rebuilt Q-Jet which just happened to be the correct number. Eventually got a stainless tank and sending unit.
http://s1355.photobucket.com/user/pj...ary/GTO%20tank

[Geoff]

Tanks are very easy to remove & once out of the car can be cleaned properly.

[ftwmlp]

Thanks for the input so far. I'm thinking even if I decide to drop the tank it would be prudent to siphon any remaining gas before doing so? Tried one of the bulb siphon jobs but cannot seem to start any flow.

[pjw1967]

Originally Posted by ftwmlp

Thanks for the input so far. I'm thinking even if I decide to drop the tank it would be prudent to siphon any remaining gas before doing so? Tried one of the bulb siphon jobs but cannot seem to start any flow.

As long as there is not more than a gallon or two, just get a funnel and pour it into a container. Either way you still have to deal with the same amt of gas.

[DOC]

to flush tyhe lines and empty a tank, I have disconnected the hose from the fuel pump from the tank and put an extension hose on that end into a gas can. then pumped some air into the tank.. not alot, jut enough to keep the flow going until the tank is empty Been doing this way for years....

[pjw1967]

Originally Posted by DOC

to flush tyhe lines and empty a tank, I have disconnected the hose from the fuel pump from the tank and put an extension hose on that end into a gas can. then pumped some air into the tank.. not alot, jut enough to keep the flow going until the tank is empty Been doing this way for years....

Learn something new every day......

[YNOBIL]

Originally Posted by DOC

to flush tyhe lines and empty a tank, I have disconnected the hose from the fuel pump from the tank and put an extension hose on that end into a gas can. then pumped some air into the tank.. not alot, jut enough to keep the flow going until the tank is empty Been doing this way for years....

I used the same system, it's the simplest way to do it.

[lust4speed]

Originally Posted by DOC

to flush tyhe lines and empty a tank, I have disconnected the hose from the fuel pump from the tank and put an extension hose on that end into a gas can. then pumped some air into the tank.. not alot, jut enough to keep the flow going until the tank is empty Been doing this way for years....

True, because you never know when using a siphon hose whether you are near the lowest part of the tank or not. The pickup "should" be positioned to pull out most of the fuel. The trick is only a little air - if you hear the tank expanding it's time to back off some.

My '67 GTO sat for 11 years with an empty tank, and there were no surprises when we poured fresh gas in it and took off. On the other side I purchased a '68 GTO a few months ago that the woman said had been sitting for 6 years (neighbors said closer to 10), and we had to drop the tank and flush out the worse smelling, vile, putrefied old gas I've ever come across. Must have been at least half a tank or more when parked. Even then, after taking the tank out and cleaning it good, there was no rust and we were able to re-install the tank with no further problems. The gas was so bad that the carb I brought over and installed on the car at the woman's house to pull the car on the trailer, ended up with enough varnish to stick the vacuum pistons on the AFB by the next day. No big thing since a little brake clean cut right through the gunk and got the carb working again. I had dumped 5 gallons into the tank before trying to start the car thinking that it would dilute and boost up the old gas, but that idea was a total flop.

[400 4spd.]

We often get in cars that have sat for years untouched. I always advise replacing the following items:
Fuel tank and all fuel hoses. Sending unit optional.
Fuel pump.
Brake fluid and hoses.
Calipers, master and wheel cylinders optional. Almost always find a leaking wheel cylinder.

And ALWAYS oil and remaining fluids and filters.

[ftwmlp]

Originally Posted by DOC

to flush tyhe lines and empty a tank, I have disconnected the hose from the fuel pump from the tank and put an extension hose on that end into a gas can. then pumped some air into the tank.. not alot, jut enough to keep the flow going until the tank is empty Been doing this way for years....

Thank you, this makes a lot of sense and I will give it a try. My garage has a slight slope and right now the rear is on the down slope. Does the tank need to be level with or above the level of the hose where it was normally connected to the fuel pump for this to work as expected?

I'm still curious about the drawing from the shop manual (see original post). I've thought it might just be a typo on the dimensions, the authors of the manual put that section in there with good intent I'm sure.

[vidguy]

Originally Posted by DOC

to flush tyhe lines and empty a tank, I have disconnected the hose from the fuel pump from the tank and put an extension hose on that end into a gas can. then pumped some air into the tank.. not alot, jut enough to keep the flow going until the tank is empty Been doing this way for years....

So you put compressed air into the filler tube? And it forces the gas out of the pickup? How do seal the filler tube? Rubber? Rags? Need more info
Very curious how you guys do this.

[vidguy]

OK I just tried this on the GTO tank. Disconnected the short rubber hose that is attached to the pickup where it was connected to the line from the fuel pump. Stuck that in gas can. Took off the gas cap and just blew some compressor air into the filler.. didnt even have to seal it.. Da**ed if gas didnt start flowing and filled the 5 gal can in no time.. GREAT TIP.

[ftwmlp]

Originally Posted by vidguy

OK I just tried this on the GTO tank. Disconnected the short rubber hose that is attached to the pickup where it was connected to the line from the fuel pump. Stuck that in gas can. Took off the gas cap and just blew some compressor air into the filler.. didnt even have to seal it.. Da**ed if gas didnt start flowing and filled the 5 gal can in no time.. GREAT TIP.

Hmm, I guess I misunderstood the first post about this method, I thought it was where the fuel line attached to the fuel pump at the front of the car, didn't have much luck there. Thanks for the clarification.

[Greg Reid]

Originally Posted by ftwmlp

Hmm, I guess I misunderstood the first post about this method, I thought it was where the fuel line attached to the fuel pump at the front of the car, didn't have much luck there. Thanks for the clarification.

Same line...different way of describing it.