Oil pressure Gauge fitting

[johnsartain]

I am trying to find out what the thread size and pitch is for the fitting that screws into the back of an oil gauge for a 1950 B2B pickup. After looking through through the forums, in search of my answer, I have found several clues but no winner as of yet. Here are the runners up...

5/16-24  - too small

3/8-24 bolt thread- wrong thread but close.

3/8-24 thread in an inverted flare fitting - wrong thread but close. 

1/8 - npt -  to big

There was one member that suggested it may be a pilot line fitting but there are three sizes, 1/8, 3/16, and 1/4 inch sizes based on the diameter of the tubing. These fitting are the only ones I haven't tried.

It may come to a point where I am left to having to try and thread it to the 3/8-24 thread for the inverted flare fitting or the 1/8 npt. I'm not sure what problems that could create and I would really rather not go that route. 

Advice anyone? This is another part missing from my truck-in-a-box.

[Jerry Roberts]

See attached photo . The line size is the same as 1/8 th inch brake line . I can send this fitting to you if you want it , You could then use a brass compression union to connect your two lines or use another method of attachment . 

[johnsartain]

Sure, I could use that. It appears to be exactly what is needed. Address will follow in a pm.

 

[JPP]

I have bought after market gauges and they use the same line as my standard gauge, I swap them for calibration purposes. Never seemed so difficult to match. 

[Jj1981]

Is the fitting bad I cut my line off under the dash and used compression fittings worked great I also have a 1950 good luck

[Jerry Roberts]

14 hours ago, johnsartain said:

Sure, I could use that. It appears to be exactly what is needed. Address will follow in a pm.

 

John , I will put it in the mail in the morning . Jerry

[johnsartain]

Thank you so much, John! I really appreciate that!

 

 

Edited October 9, 2017 by johnsartain

[johnsartain]

9 hours ago, Jj1981 said:

Is the fitting bad I cut my line off under the dash and used compression fittings worked great I also have a 1950 good luck

My problem was that I never had one with the gauge.  Someone had already taken it for their vehicle. it had been removed from the truck. When I mentioned in the original post that I had a truck-in-a-box, it wasn't a joke. A good many of the parts were there  but there were also a few missing, this being one of them. The engine was removed and there was a line lying in the bed with both ends cut off and the gauges were one of the parts that were in a box in the cab. Bit it's all good now, this may be the very last part I need except a new set of locks and keys.

[RatMan]

Reviving and old thread. 
 

Has anyone ever determined what the we actual thread size is for the oil pressure gauge? I have a 53 Plymouth with a 218. I cannot figure out this thread size. I would like to adapt a regular nylon oil pressure line to it if possible. 

[Young Ed]

It's a special fitting but I'm not sure of the thread. When you crank it down the first time it snaps in two and part of it presses onto the line. 

[JBNeal]

additional information - oil pressure gauge fitting

[ggdad1951]

7 hours ago, JBNeal said:

additional information - oil pressure gauge fitting

 

did it work?  If so great info on the part!

 

@Young Ed didn't we find that part at Beishwingers? (sp)

[Young Ed]

1 hour ago, ggdad1951 said:

 

@Young Ed didn't we find that part at Beishwingers? (sp)

Yes and I've ordered a few and sent them off to other forum members

[B1B Keven]

I have a bunch of these fittings. The lines have been cut.

[PT81PlymouthPickup]

I wish I could remember the thread size, I do remember it giving me some grief. Lols! ?  If you measure the O.D. of the threads that will be very close (usually a few thousands under a nominal size) For example; 3/8 would measure a little under but close to .375. If you have or can borrow a pitch gauge you can determine the pitch (threads per inch). It may have an odd pitch. Best to do that under some magnification especially if you're as old as I am. You would need a new ferrule and possibly bend up a new line if you didn't want to splice a used one in. I got one somewhere, but just didn't record where. Would be nice to know if you determine what that fitting is.

[Tooljunkie]

If i recall, its referred to as  a 3rd sleeve fitting. I just pulled a gauge set out of my parts truck,the tube is still intact. Havent checked my 3rd parts truck to see if line is intact. 
 

reading the technical specs on the mcmaster carr link, its 3/8-24. 

[bkahler]

Is this the special nut being discussed?

 

 

[JBNeal]

That Amazon item looks similar to the McMaster but it appears unavailable now...

[bkahler]

46 minutes ago, JBNeal said:

That Amazon item looks similar to the McMaster but it appears unavailable now...

 

I've had the amazon nut on order for quite some time with no ship date given as yet.  I didn't even think of checking with McMaster.  I'll go ahead and order from McMaster so I can get the oil line ran.

 

Thanks!

 

Brad

[David A.]

The best I can remember, the only fittings I could find were 3/8-24. However it didn’t want to screw in exactly right. It acted like it was tightening down but it leaked something terrible. Turns out it was just the threads getting tight and it never actually compressed the ferrule. I used a thread pitch gauge and found the oil pressure gauge was 27tpi. I never could find a fitting with that thread pitch, so I ordered a 3/8-27 die and used it on the fitting. It seemed to do a great job on the soft brass threads. It screwed right into the oil pressure gauge and tightened up against the ferrule. No leaks as of yet. 

[Young Ed]

I still have some of the ones I bought as mentioned in that other thread. They are hard to install the first time but they do work as they should.