Oil Gauge Rear Fitting

Just put one in and used this type

https://walcks4wd.com/Oil-Gauge-Hard-Line-MB-GPW-CJ2A-CJ3A_p_1460.html

 

Why not use the white nylon line that attaches with ferrels. Definitely not AN. You can also use a regular flare fitting if you want to stick with soft copper.
-Donny

 

It is a copper flare fitting, so it is the same as AN/JIC. It would be a small one.

 

Lets just call it a 37 degree SAE flare fitting. AN is military aircraft spec which is the reason for my response. Yes, they are both 37 degree, but the tighter thread tolerance of AN doesn’t always fit SAE fittings. Dan is likely looking for an 1/8 flare, unless his gauge accepts the ferrel barrel and nut.
-Donny

 

Soooo, is the flare fitting actually part of the gauge? Most have 1/8 npt threads on the gauge and then a fitting to adapt to the 1/8" flare line. If you have 1/8 npt, just get an AN3 or AN4 to 1/8 npt and run something that will both flex and that you will not likely have to mess with again. I have had better luck running the 1/8" copper than I have the nylon but both suck for longevity where you need a flexible connection. Nothing like a waterproofing job on your shoes while piloting a CJ-----------

 

Been there, done that. I had run a 1/4” copper line to my oil gauge, and a couple years later while driving, I felt my pants leg was wet and warm. I probably lost close to a quart before I knew what was happening. Lesson learned; never run a 1/4” line to an oil gauge!
Dan, if we could get a photo of the back of the gauge you have, we wouldn’t be guessing. There are several configurations depending on the brand, application, and age of the gauge.
-Donny

 

Been a while since I looked at a stock flat fender oil pressure gauge, but I think the flare fitting is part of it. The stock lines that feeds it is steel.

 

Put a short pice of flared tubing, convert that to a pipe thread and then you should be good to go. I know it’s a lot of fittings back there.