Oil Pressure Gauge Issue - Help Needed.

Got my Farmall 240 to the point I had it running this morning. Have a small problem with the hook-up of the metal line to the gauge. The original gauge to the tractor opening on the back is somewhat larger then the new gauge I am replacing it with. I'm using the brass connector between the gauge and the pressure line. I believe the hole in the back of the original gauge would permit the end of the pressure line to enter the gauge slightly. The replacement gauge is too small and I believe the tube is bottoming out on the gauge. When tightening the nut against the ferrule I believe I am not getting it seated correctly to the gauge. I might have a problem in that the original pressure line needs trimmed off a small amount so the retaining nut can tighten and seal the ferrule to the brass connector. Or maybe the back of the gauge needs opened up slightly so the line can seat instead of the existing interference on the gauge.
Has anyone run into this issue and what is the proper resolution - gauges are either NOS or obtained from CaseIH. Any solutions or comments are greatly appreciated, Hal.

The original may have had a brass fitting that adapted the flair to the gauge. The ferrule must be pinched in both the gauge and line sides. Thus there must be a tapered place for the gauge end of the line to enter, allowing the ferrule to push against it. If there is not it will not seal. Take the line and gauge to a NAPA or other real auto parts store, or real hardware store to assure of the correct adapter. Jim

Jim, I appreciate what you are saying and feel I need to discuss this matter further as I think the sealing feature is within the brass coupling. Around the mid-point of the brass coupler is an area where I believe the seal is to take place and not on the gauge itself. The rear of the gauge is tapered pipe threads which seals easily to the brass coupling. The issue is the placement of the ferrule approximately an inch or less from the end of the tube. I believe since the length of the tube beyond the ferrule is too great it can not seal on the internal sealing surface of the brass connector thus I have a small leak around the small opening between the tube and seal nut which is behind the brass coupling. If you would provide me some contact information - my email is open - I can discuss this further and by putting a quick sketch together I think you will see the issue to resolve. By the way, the original gauge part no. is 362093R93 and the replacement gauge is part no. 536962R2. Thanks for any additional information you can provide, Hal.

THere is no problem removing material from the end of the line beyond the ferrule. If it is an inch, it has been put in too far out of casual assembly, not because it is correct. The ferrule must seat, the line beyond the ferrule can be as short as 1/8" with no leakage. Just cut off the line so it goes into the adapter readily. Jim

Jim, I think that is exactly the problem because first I put the brass connector onto the gauge unit and tried to insert the line into the connector and it wouldn't go in far enough to get the nut behind the ferrule started. I then removed the brass connector from the gauge and started the nut behind the ferrule and then screwed the connector back to the gauge. It was very difficult to move the sealing nut forward any more to obtain an adequate seal on the machine surface inside the connector. I was just unsure what to do to get it sealed up to the gauge and didn't want to "toast" the gauge before trying to obtain a resolution through this group of very talented individuals who in some cases have already been there with the same issue. Thanks for your advice in this matter and I will have to remove the dash again (no fun job) and elevate it somewhat for some hands room to have at the resolution. Thanks again for your comments and suggestions but some quick measurements will determine what amount to remove to obtain a good seal in both places, Hal.

You should post several pictures of the connection. Hal

Hal, I would love too but my camera abilities go back to the Kodak Brownie days which I could barely handle then. Don't have a digital camera and wouldn't have a clue how to load a photo if I did. I certainly need to upgrade and gain a little education along those lines. I retired in 2002 and was still using my slide rule so I'm just an old schooler and little outdated.
Basically, it is .125" tubing with the ferrule about .75" from the end where it seals in the brass coupling. The coupling is approx. 1.25" long with different threads on each end which has an internal sealing surface about the mid-point for the ferrule to seat and seal. On one end it is threaded to mate with the gauge unit and the other end it threaded to mate with the ferrule sealing nut. The original gauge p/n 362093R93 has a large opening in the back which would allow the tubing to fit inside the gauge while the new replacement gauge 536962R2 has a very small opening on the back which is smaller then the tubing diameter. Problem with the original tubing is the placement of the ferrule as the tube end is against the gauge and the ferrule cannot be brought to contact the sealing surface in the brass connector with the sealing nut. I am going to reduce the end of the tube beyond the ferrule to eliminate the installation interference as suggested by Jim. Thanks much for your comment and interest in this issue. I certainly wish I could provide some photos which would make the visualization of this issue quickly apparent, Hal.

That slide rule is probably a collectors item now.
Measure the diameter of threads on the new gauge. 1/8 pipe threads will measure .405". Hal

Jim, Additional information I obtained from CaseIH on the oil pressure replacement gauge p/n 536962R2. It is noted as a serviceable replacement for the original gauge p/n 362093R93 - so I believe I now have an understanding of what serviceable replacement must relate too. Thanks very much for your comments and participation in this thread, Hal.
P.S. The gauge faceplate with the IH logo and part no. 536962R is noted along with a patent no. and states the manufacturer as Rochester Gauge Company, Dallas, Texas USA. Did the gauge company relocate from Rochester, NY to Dallas at some point as I also have a new replacement fuel gauge (which I'm not using) with the same notation as to it's point of manufacture. I later found an original NOS 371056R91 fuel gauge manufactured at the Rochester, NY location which I decided to use.

Hal, That is exactly what the brass connector is for. The gauge end is 1/8" pipe thread while the other end is for a 1/8" tube ferrule and seal nut with a ferrule sealing surface machined inside the connector which has a center opening large enough so the 1/8" tube will fit through. Both of the gauges have the same 1/8" pipe threads on the back it is just the opening size on the back of the gauge unit that is different which is causing this to be a serviceable replacement gauge as noted by CaseIH. I obtained a small diameter tubing cutter this morning so I'm good to go on reducing the length of the tube beyond the ferrule to remove the interference with the back of the gauge unit which will then allow the ferrule to be sealed internally to the brass connector. It was certainly nice to have a couple like you and Jim involved in this issue so thanks again for your contribution, Hal.

Just some more information on hooking up the new replacement oil pressure gauges that come with a male pipe thread. The CASEIH part number for the adaptor fitting is 257523R1 and if you need the nut with ferrele that slips on the pipe like original the number is 19984R1.
That nut is the same style but smaller size just like used on the original gasoline lines on all the H and M's and numerous other IH tractors. Seems to be a lot of confusion over that as IH did not use flared fittings or more conventional ferrele type with the male threaded fitting where a female threaded nut screwed onto the male . The type IH used is difficult to find in ordinary parts stores or hardware stores.

Thanks Pete for the supplemental information but I think I have the correct parts as both gauges have the same male 1/8" pipe threads and I'm using the original brass connector between the original 1/8" steel line with the ferrule and the gauge unit. Don't have a problem with the fitting working just fine it is just that too much tube is past the ferrule which contacts the back of the gauge without sufficient clearance to permit the ferrule to seal against the sealing surface within the brass connector. I certainly appreciate the part no. information and will run a copy to keep in my parts catalog. Thanks for sharing, Hal.