1500 oil pressure gauge leaking

[Tipsy]

So, I'm driving to the store the other day and all of a sudden I feel a drop of oil on my leg. I look down and discover that my oil pressure gauge is leaking. I'm driving a '76 midget. I've pulled the gauge from the dash far enough to remove that oil line from the back of the gauge. It looks fine. I'm going to reattach it and give it another try. My question is, should I use any sort of sealer on the fitting threads? Like I would in a house plumbing situation, or are these meant to dry fit together?
Thanks!

 

[dklawson]

If your gauge is a Smiths and came with the factory tubing on it, there is a fiber washer sealing disk that goes between the male gauge stem and the inside of the fitting. If that seal is missing, you probably could use a suitably sized o-ring. When I have fitted Smiths mechanical oil pressure gauges to cars where they were not standard, I have used the copper tubing installation kits available from most parts stores. Those kits come with 1/8 NPT female to 1/8" tube compression fittings. The female 1/8 NPT threads should not fit the straight BSPP threads on the back of the gauge, but they really are close enough that applying a couple or wraps of Teflon tape to the gauge stem creates a very serviceable seal to the fitting.

 

[JPSmit]

teflon tape - and I'm not sure mine had the sealing disk (also a '76)

 

[Tipsy]

Hard telling what's original on this car. It was in a wreck many years ago and was rebuilt. Many original items like all the smog equipment, entire heater system, etc. are missing. Original color was green but now it's red. I believe the gauges are original and this is a Smith's dual gauge. There was no fiber washer but I can put in an o-ring and some teflon tape. Water temp gauge reads low all the time, it does rise and fall as it warms up but only rises a little. Never up to the "N" as it should. Does anyone repair these? The only MG mechanic in my area is no longer in business so I have no where to go.
Thanks!

 

[dklawson]

Dual gauges are expensive to repair professionally. Typically it costs about the same to replace as it does to repair. The exception to that are the more unique, older gauges on some of th Healeys and older MGs.

That said (depending on your comfort level) you could repair the temp gauge yourself. See this link:
https://www.ply33.com/Repair/tempgauge
I have repaired two gauges using the method shown in the link.

There are some caveats about the process but I won't go into them here. You can use the search feature of this board (checking all forums) and you'll find several threads where this was discussed in depth during the past year or two. The only warning I'll offer here about the repair process is to caution you that IF the needle on temperature portion of your gauge does not return to its stop peg on the left (if it doesn't read below scale cold when it's cold), then you should assume the bourdon tube is deformed a bit and that more extensive recalibration will be required than is discussed in the link above. Save the repair method in the link for a gauge whose temp needle is sitting on zero.

 

[JPSmit]

Water temp gauge reads low all the time, it does rise and fall as it warms up but only rises a little. Never up to the "N" as it should. Does anyone repair these? The only MG mechanic in my area is no longer in business so I have no where to go.
Thanks!

before you do anything repair wise, make sure the needle isn't binding on the glass. Mine was. If you can get the gauge, glass off and sensor in boiling water, you shoul see what happens BEFORE you remove it - don't ask me how I know

 

[Tipsy]

Well, finally got around to working on her again. Put in a tiny o-ring and that stopped the oil leak at the gauge. Got the glass back on the gauge and back into the dash (no easy task as I'm sure you know!) Then set out to change anti-freeze as I had not touched that yet since I bought the car this summer. Took off thermostat housing to clean and replace thermostat and what do you know! Old thermostat was in three pieces! That explains a rattling noise I kept hearing but could not figure out. Drain it all and refilled with new thermostat in place. Fired it up, ran it for a bit and now the temp gauge reads the way it should! Boy am I lucky! PO's mechanic had removed sender and installed an aftermarket gauge because he thought it was no good anymore. Doesn't say a lot about his qualifications.
Thanks to all of you for your help!