1955 Coupe Deville Fuel Tank Fitting

[snoridr182]

I have tried everything I can think of and I cannot find a male threaded fitting that fits into the gas tank. I am aware of the stock ferrule and I will deal with that issue later. All I am trying to do is get the correct male threaded fitting that fits into the stock tank. I can't seem to find the right thread size or pitch.



PLEASE HELP BEFORE I LOSE MY MIND!!!!

[Bill Balkie 24172]

Hello ,
    Did you try a   Male  5/16 inverted flare fitting . Then you woud need the correct ferrule fitting . I can help you out with Ferrule fitting .

     Good Luck,
         Bill

[snoridr182]

I have tried 5/16 inverted flare and it doesn't fit. It seems like it should but its a touch to big

[snoridr182]

Bill


I would take a couple ferrules off your hands though. How would you like to arrange a sale?

[55 ledsled]

I have a 55 Cad and had to have 2 fittings to make it work. One of them was a compression fitting from the fuel line, screwing into the ball-end fitting that fits the tank. I found them at Ace Hardware in the pipe and gas fittings area.

[Bob Kielar]

I believe this is the fitting that goes from the fuel line to the tank. The last picture is a 1/2x20 nut just to show it’s not a pipe thread that goes into the tank.

Keep Cruzin,

Bob Kielar

[55 ledsled]

That's the area of the store I found mine in and it fits like a glove. Good luck!

[snoridr182]

When I measured mine; I get 0.4375 on the Minor thread which leads me to believe it 0.45 on the Major thread. That doesn't exists that I know of


I've already tried 1/2 - 20 and it stripped off the first thread on the new male fitting almost immediately

[Jeff Rosansky CLC #28373]

Just a couple of quick thoughts.... Are you sure it is the correct tank? Has it been modified on any way such as a new fitting welded onto the tank? Mine was missing the ferrel and held together with JB Weld.
If the tank is out of the car I would suggest going to a plumbing supply place with the tank and see what they can do to find a fitting. If you have a Pirtek or local place that fabricates hydraulic fittings may be able to help you as well. The local Carquest helped me. I am trying to put a link in here but it isn't working. See a thread by me on this topic from 9/10/2017.
Jeff

[55 ledsled]

As a last ditch effort, you could just plug that bulkhead and drill a new hole and place in a new fuel cell bulkhead with a pickup...that is if you weren't going for originality. Drain the tank, stick a reversed shopvac into the filler with the drain left open, turn it on for a while and dry it out before drilling.

https://fuelsafe.com/fp181/

[Daryl Chesterman]

Please see the website below for all of the measurements for American fittings.  It also includes metric fitting measurements, but on an older Cadillac, I don't think that is even a possibility!!!

https://www.hydraulicsdirect.com/Fitting-Thread-Chart-s/1934.htm

Take a small, bright light (like a pen light), and try to get a thread count with a thread gauge.  This will give you the best starting point, along with using an accurate caliper to measure the opening diameter.  When using the bright light, examine the condition of the threads to see if the first thread, or threads are messed up.  If the first thread is messed up, there is no fitting, even the correct fitting, that is going to get started properly.