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Leaky Oil Pressure Gauge

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60TR3A

60TR3A

Jedi Trainee
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My '61 TR3A has suddenly started leaking oil from the the oil pressure gauge, a few drops every few minutes, maybe one drop per every 2 minutes, plus or minus. I couldn't reach it myself to try tightening the line in case it had loosened by normal driving vibrations so I had the local gas station do it for me. The mechanic said it wasn't loose but gave it a little tightening, nonetheless. That didn't help at all and it leaks just the same as before. He said it's probably the coupling. My question is: can the coupling be changed on the end of the line the way you change a compression coupling on a household water filter line or must I replace the entire line, coupling and all? The gauge seems to work perfectly, albeit leaky. I'd hate to have to replace the gauge to stop the leak. Any suggestions?
 
IIRC there is a little leather seal where the line connects to the guage. Maybe it finaly gave up the ghost and started leaking.
 
Cool. All is not lost, after all. Shall go find one online and order it post-haste. Thanks!
 
I found these parts on Moss Motors' website but I don't know if these are for the engine side of the oil line or the gauge side (or if they fit both sides). Anyone know?
 

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Aloha,

I'm not sure from your description of where the leak is. The copper washers from Moss you refer to are to seal the oil pressure line take off near the oil pump. Often these copper washers can be annealed (heated red hot and then quenched in water) and then reused. The oil line goes over near the fuel pump where it connects to a flexible line, from the that to another solid line to the oil pressure gauge. All of these fitting are compression fittings. The smoothness of the compression fitting and mating surface really form the seal. If your leak is at one of these joints, open the connection and cleaning the surface and carefully reconnecting may seal it up. If it is leaking from inside the gauge, the bourdon tube maybe leaking. If this is the case, the gauge will need to be repaired.
 
Aloha,

It's leaking from behind the gauge onto the carpet of the transmission hump. So I guess I can't use those fittings, huh? The gauge works fine so I am assuming the connection to the line needs a gasket or the fitting needs to be replaced. Won't know until someone yanks out the gauge, I guess.

Mahalo,

Jeff
 
Most likely you don't need to pull the gauge. Just undo the fitting, remove whatever is in there (if anything), replace the washer and tighten it up again. Don't go overboard on the tightening, though, since the gauge won't take much torque.

Unfortunately, I don't know of a source for the washer (which as noted was originally leather). ISTR I found a nylon washer in my hardware stash that would fit, but I don't recall the size offhand. Might have been #4.
 
I've ordered a replacement copper line with fittings from TRF and that should do the trick.
 
Does it come with the gasket? I thought the gasket was included with the gauge ...
 
It might not come with the gasket but even so, my mechanic can come up with something, I'm quite sure.
 
A 007 "O" ring has always worked for me. Find someone locally that sells them individually so you don't have to buy 100 !! Tell you mechanic, he may have a source for that size.
FRank
 
I have two connection fittings very close to the back of the oil pressure gauge on my 1958 TR3A. This photo is from 2007 but is how it came new in 1958.
 

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Thanks for everyone's help! I have a replacement copper line en route from TRF so hopefully my mechanic will come up with the necessary gasket and make it stop leaking. I still drive the car and am enjoying the heck out of it (when it's not in the 90's as it has been lately!), but getting oil drips on my right leg and having to keep a rag on the transmission hump is getting old. I should have it all fixed this week, and if my mechanic runs into any problems at least I'll be able to show him all these helpful hints, so thanks again!
 
It doesn't show on their website, but the latest (T24-110) Moss catalog shows this as part # 435-515 'WASHER, leather for [oil] pressure gauge'.

Interestingly, 435-515 is on their site for lots of other applications varying from oil gauages to tonneau snaps.

My wife has instructions to never discard a leather purse, shoe or wallet until I get to salvage any good leather. Quite a few useful parts and many emergency repairs can be effected with a piece of leather.
 
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