My first trip to the dragstrip

[Ratbird]

Thx gents, I'll get to the new fuel line in the next month or so for sure. Bud, what is a 3/8 pick up? Is that the gas tank pick up? I believe my fitting on the gas tank is welded into the tank so i don't know how I would make it larger?

[machoneman]

It is the gas tank pickup. On most, the pickup and sending unit are combined in a removable piece that drops into the tank. It's been a long time since I've even seen a 'Bird like yours but if the fitting is welded, you need to drill it out and have a 3/8th's line welded back in. That or figure out how to use the existing sender disc by drilling a hole in it and welding a spout ala' a '63 ford.

http://www.classiccarautoparts.com/images/pics/S-F4WOV.jpg

[Ratbird]

Thx Bob, mine is like this one and has the pick up built into the bottom drivers side corner; http://www.ebay.com/itm/NEW-1958-1960-Thunderbird-T-Bird-gas-fuel-tank-MADE-IN-CANADA-In-Stock-/131184363022?_trksid=p2054897.l4275

There is a drain plug on the opposite side bottom corner. I think I'll see what size the drain plug is and see if I can maybe put a fitting there. Either that, or I'll maybe see about changing out to a unit like you showed and plug the bottom two holes. The only problem with that is that the line would be exposed in the trunk and I wouldn't be able to put anything in the truck unless it was secured down - wouldn't want items in the truck to bend or break it.

Dave J

[thatdarncat]

Forgive me, I've never looked that close at the gas tank of a '59 so I could be wrong, but if your tank is like the one in the link the sender and pickup assembly goes in the hole at the top of the photo opposite the filler neck. That would be at the top front of your trunk. Are you sure someone didn't modify yours? If it does turn out yours has a sender and pickup assembly similar to the one in Bob's link a larger pickup tube can be added to the disk. You may even want to retain the smaller diameter original pickup tube on the disk to use as a return someday if you changed to electric fuel pump. Maybe take another look in the trunk?

[Lenz]

The setup Ratbird described kinda reminds me of what I had in my '57 Ford Tudor.  The fuel draw line was at the tank bottom with a drain plug opposite.  the tank looked a lot like the one in the photo with a behind the gas plate filler neck, only narrower.  The fuel gage sending unit did go thru a smaller diameter disc in the tank center top you could access through the trunk.  The tank was vented through a tube that snaked around in the left rear quarter and exited somewhere below.

[Ratbird]

Len is right on the money, it's just like he described except I don't know about a vent of any kind. I replaced the original tank and kept it completely stock. As far as I know the gas cap is the vent. I had to order the correct cap, there are tons of different ones that fit, but you need the correct one to go with the original tank. Whenever I remove the cap I get a big "hiss" from the built up pressure. I believe the vented cap lets air in, but not out???
I'll double check the line at the tank as soon as I can, but my memory says it's a flare fitting with the nut on the fuel line - 5/16 inch.

regards, Dave J
 

[Lenz]

Dave, that heavy pressure build does not sound right to me.  I've seen slight amounts before as though the cap would permit a pound or two (my '74 F250 did it in hot weather), but never as heavy as you seem to be describing.  The vent tube in my '57 was 1/4" hard line that came up through the trunk floor at the extreme left and exited in the fuel tank filler tunnel behind the license plate.

If I'm wrong about the pressure I'm sure other members can correct, maybe your gas cap is at the root of your troubles or was designed to work in conjunction with another venting component?

[drdano]

Whenever I remove the cap I get a big "hiss" from the built up pressure. I believe the vented cap lets air in, but not out???

That is correct.  For emissions pressure is let in, but not out.  My Galaxie did the same thing.  Last summer in the heat I stopped at a gas station to tank up, went to unscrew the cap and the pressure blew the cap right out of my hand.  I couldn't find a vented cap that would vent both directions, so I drilled a super small hole that I think will help.

[machoneman]

I have seen poorly made vented caps that did nothing of the kind.  While the cap itself had the requisite vent hole, the design and placement (at the edge) of the gasket totally sealed the tank, hence no venting!

Try this: pop the cap and leave it off,  duct tape the entire filler opening, poke a 1/8th" hole at the top edge of the tape and take a drive.

On edit: yes, all modern caps only allow air in, not out. Keep in mind that pretty much all older cars had a separate steel vent line (some with a rubber hose section) to vent gas fumes under the car. If that vent tube is blocked with decades of crud and the cap is sealed (non-vented) that could be your issue. 

[Grbmaverickmo]

My 54 use to have the same issue on the top end. It was the gas cap not venting the gas tank must have been vacuuming tite and the pump couldn`t pull anymore fuel. Drilled a small hole inside the vent on the cap and it worked fine at the track. Sounds goofy but it worked for me

[Ratbird]

Hm, I'm a little confused. For starters I think I'll ask the guys at the "squarebirds.org" web site. They are experts on these old T-birds and will know what kind of cap it should have stock, and how it should work.

My gas tank is only a year old and doesn't have any kind of tubing or venting lines or hoses. The original that I removed was the same - identical. The pressure I feel when removing the gas cap depends on how much gas is in the tank, and how much sun is shinning on the trunk. I'm pretty sure it's OK the way it is. Sadly, I can't really test it because the drag strip is 100 miles away, and we have no roads anywhere around here to make a few hard runs.

I'll look inside the feed tube and see if there is a tube coming up. I'll also check out the inside of the cap to see that it is OK.

stay tuned....... 

[machoneman]

Good idea but....

If the tanks (old or new) didn't have any welded-on vent tube, the OEM tank had to have had a vented gas cap....or else!

http://www.youtube.com/watch?v=Zz95_VvTxZM

Btw, this is not a photo-shopped  vid. Having working for tank truck carriers, rest assured all at one time had a similar over the road tanker that got sucked in when the driver forgot to hit the vacuum break lever on the top, usually over the manhole cover,  before starting up the pump to empty the tanker. Ouch!

[Ratbird]

WOW! that's a lot of pressure in that video.

I've been away so I'm only just getting back to this.
My tank has no tube etc coming up to the cap. The cap has a plastic piece on the inside with small holes in it, I'm sure it's a vented cap and correct. What I'll look at tonight is the outside of the cap to make sure it's not got something impeding the air coming in. I wish I would have known or thought of this at the track. I would have tried the tape and small hole idea then.

Dave