New tank 57 fuel tank Question

[Bill Balkie 24172]

Hello ,
   I have purchased a new fuel tank for my 57 Cadillac , However i do not need to install it right away because the old tank is still ok but may need to be replaced soon  .  I want to have all new  fittings in place to use on the new tank . I have some time to track them down .  When i talked to the tank manufacturer about the type of fitting i need the only answer i get is the existing fittings will match perfectly . I would like to have this tank ready to go with the new fitting in place so i can test for leaks and who knows maybe i might distroy the old fitting when removing them from the old tank .  This is what puzzles me . The new tank has to open fitting with two differant thread sizes and fitting configuration . The fitting on the far left is plugged on the tank that is in my car now , so i intend to plug the new one as well  it accept a  thread that is on a 1/4 inverted flare however the configuration is not the same and the seating surface is about 5/8  of an inch deep inside the fitting . The fitting on the right is the one that feeds the fuel pump .  this fitting has a thread that is the same as 5 /16 inverted flare fitting but has a strange configuration that is not fixed to the nut . in other words it floats inside the nut housing .  Can anyone  tell me what kind of fitting are required to connect the fuel line and plug the other line ? I have added a picture .

  Thanks ,
       Bill

[Jeff Maltby 4194]

Hi Bill. Does your tank fitting have this flare in the bottom and if it does, it shouldn't require anything other then the fuel line to seat properly into the tank nut, so this style would be just like a brake line into a wheel cylinder.

Pre 49 tanks used this style that didn't require any bushing (least an oem 48 tank I had did) and thus, why they changed to a brass bushing in 49-58 only is beyond me, so what style was used on 59 up ?

[Bill Balkie 24172]

Hello Jeff,
    My fitting does not look like the picture you posted .  that fitting looks like it 's  for an inverted flare .the fitting in the new tank  where the fuel comes out of has a floating fitting within the nut itself .  Please check out the picture i posted a few post ago .  If i removed the inlet line from my old tank it will probably work . but i would like to have fittings just for this tank . It is like some sort of mystery about these fuel line fitting . Didn't they use standard fitting ? and if they did they must have a type and a number of some sort .  Jeff , did you get the message i sent you earlier ?

   Bill

[Bill Balkie 24172]

Hello Jeff ,
      The fitting on the new tank  has a internal thread that a 5/16 inverted flare will fit into . however in the bottom of the thread is a counter sunk tube that is free floating . you can move it side to side and in and out .  very loose  but it does seat itself solid in the tank . .  the fitting that you sent me  looks like it has the proper angle to accommodate  a 5/16 inverted flare on both ends . I think it will work but i will have to machine about .06 off the outside Dia. of the fitting . i think it will be OK .

     Thanks,
           Bill

[Jeff Maltby 4194]

Got you Bill. Is this your tank ? http://www.ebay.com/itm/1957-CADILLAC-GAS-TANK-FUEL-TANK-STAINLESS-SENDER-/230592955714?pt=Vintage_Car_Truck_Parts_Accessories&vxp=mtr&hash=item35b0694542

A 49 fuel line screws in about 3 threads with bushing installed.

Take a picture/measurements of your fitting when you remove it please.

Jeffo

[Bill Balkie 24172]

Jeff,
  That is my tank , I will do that, but it might not be for a few weeks yet .

  Thanks again ,
        Bill