I have the factory fuel tank I'm trying to reinstall in my 71.  I've replaced the vent hoses but the gas filler hose (#9 in drawing, if I attached it correctly!) to the tank is original.  I'm having trouble getting the tank filler neck to fit back into the bottom of the gas filler hose. 

The vent hoses don't seem to be binding but the tank filler neck doesn't want to fit back into the original gas filler hose.  When I align the tank and filler hose, it looks like the filler hose diameter is too small to allow the tank filler neck to slide up into it. 

Any thoughts on what I can try would be appreciated.  Thanks  

Try applying heat.....the rubber should soften up to slide over the neck. Don’t get the heat gun too close to the gas tank or the fumes could cause a problem lol.

18 minutes ago, Diseazd said:

Try applying heat.....the rubber should soften up to slide over the neck. Don’t get the heat gun too close to the gas tank or the fumes could cause a problem lol.

Yes, what he said. The fuel makes the rubber stiff. When you remove it from the tank it can shrink some. Some heat should help make it more pliable but gas fumes are really dangerous around heat guns and blow driers and they are heavier than air. You could always use some boiling water if you could figure out how to apply it to the bottom of the hose

If fumes are still present drop some dry ice into the tank. When you can see the CO2 vapor coming out the filler, it's safe.

CO2 is a clear colorless gas.   

2 hours ago, WiZeguy said:

When I align the tank and filler hose, it looks like the filler hose diameter is too small to allow the tank filler neck to slide up into it. 

Sounds like you haven't even got it started yet.  You might try wrapping the neck of the tank with something like Mylar sheet in a cone shape, or stick a bunch of zip ties up the rubber tube as you try to get it started on the metal tube from the tank.  Make a ramp of sorts for the rubber, along with some type of lubricant.  Once the edges of the rubber are are over the edge of the metal pull the Mylar or the zip ties out then see what happens.  I'll bet some long zip ties would help you get it started and would pull out easily.

You might also be able to temporarily stretch the mouth of the rubber tube using some kind of cone shape jammed in it for a while.

1 hour ago, Patcon said:

Yes, what he said. The fuel makes the rubber stiff. When you remove it from the tank it can shrink some. Some heat should help make it more pliable but gas fumes are really dangerous around heat guns and blow driers and they are heavier than air. You could always use some boiling water if you could figure out how to apply it to the bottom of the hose

Thanks to you both, Patcon and Diseazd.  I'll give some heat a try.  Fumes shouldn't be an issue since the tank has been out for over a year...! ;-(

6 minutes ago, Zed Head said:

Sounds like you haven't even got it started yet.  You might try wrapping the neck of the tank with something like Mylar sheet in a cone shape, or stick a bunch of zip ties up the rubber tube as you try to get it started on the metal tube from the tank.  Make a ramp of sorts for the rubber, along with some type of lubricant.  Once the edges of the rubber are are over the edge of the metal pull the Mylar or the zip ties out then see what happens.  I'll bet some long zip ties would help you get it started and would pull out easily.

You might also be able to temporarily stretch the mouth of the rubber tube using some kind of cone shape jammed in it for a while.

Zed Head - that's another good idea.  I like the zip ties & lube concept, (doesn't sound a bit Dexter-ish at all!) maybe in combo with the cone idea.  Thanks, much appreciated!

If you get too frustrated with your old hose it looks like there's some OEM ones on ebay, but they'll run about $125.00. I went the new hose option last year. Replaced all the vent hoses and filler hose except for the one on the top of the tank. That hose was still in really good shape. The new filler hose was nice and soft and went on no issues. This also eliminated the fuel smell in the cabin. I couldn't see any cracks in the old hoses, but I think the filler hose seal was bad around the gas cap.

https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=240z+fuel+filler+hose&_sacat=0

w3wilkes: Thanks for the tips.  I have been debating replacing the filler hose while I'm at it... It looks like its in good shape but I did have the typical gas smell in the cab.  (Wrote it off to the vent hoses a mouse chewed through near the expansion tank and met his demise.) If the tips above don't work I'll hit ebay.  Much appreciated!