Oil Pressure Gauge seal

[rixter]

Hello,

I was cleaning up my dash oil pressure gauge today and have a question about the oil line to gauge connection. Is there supposed to be a seal there? There was the remnants of "something" there, but I can't tell if it is just crud. If a seal is to be there, what material was used?

Thank you
Rick

 

[puff4]

I believe there was a small rubber gasket/grommet.

 

[rixter]

Kevin,

On closer examination... with glasses and a magnifying glass (It's beat getting old), I saw the remnants of rubber on the end of the threaded connection. It came off. So I should be OK with an O-Ring on there?

Thanks
Rick

 

[65beam]

The parts book does not show an O ring. Your first photo clearly shows the male tubular fitting on the end of the gauge. The fitting on the oil line is a female fitting that the gauge fitting slides into. When the coupler is tightened down the two fittings seal if both fittings are clean. I have new gauges and oil lines so I'll try to take photos showing both fittings.

 

[sunalp]

I've never seen an O ring there either. Just as a precaution against leaks I wrap the threads with a little
teflon tape. Probably overkill, but I've never had an oil leak in the car.

Cheers!
Steve

 

[hartmandm]

Where would the cork washer have been installed on the oil gauge?



Mike

 

[65beam]

Where would the cork washer have been installed on the oil gauge?

View attachment 19394

Mike

Good question. That washer only appears with the gauge listing for the one gauge that supercedes the series 5 gauge starting around the last few days of March, 1966 and doesn't specify specific use and is not shown or listed with any of the fittings of the oil line. When did the switch from the metal oil pressure line to the black plastic line take place? The plastic lines and the same basic gauge other than face and mounting was used after the series 5 production ceased and fastback production started. The gasket is not listed in later parts books so who knows. I 've never run across it on the few series 5's that I've had.

 

[Mike O'D]

Teflon tape or pipe dope only works on tapered pipe threads, which these are not. The seal is at the end face of the gauge fitting and the end face of the oil line fitting - the threads have nothing to do with the seal. An O ring or soft washer is a good idea. I don't know if they came that way or not, just make sure it is oil resistant. It is possible to get a good metal to metal seal - brake lines for example. It will just be much easier to get a seal with a gasket or O ring.

 

[hartmandm]

I think if the cork washer was only relevant to the last oil gauge entry, there would have been a "brace" symbol to group the cork washer entry with the oil gauge entry above it, like the example below. Of course, the Parts Manual accuracy is always a question mark.



This thread is of interest to me, as I need to refurb my oil pressure gauge. It will be interesting to see if there is any sort of seal inside the oil line connection when disassembled. Good info here.

Thanks,
Mike

 

[puff4]

You could, of course, contact Nissonger and ask them... they're certainly going to know for sure.

 

[65beam]

This is another of those situations where not every one seems to agree so it's what ever makes you comfortable.

 

[Rick Young]

From a Plumbing stand point flared or ground joints do not require sealant or a gasket.
My TR has a flat metal to metal connection and has a cork washer.
Rick

 

[Billm]

When I went to replace my dash lights with led bulbs I found the oil line fitting leaking. I ordered a used oil pressure gauge a while back. It came with a short piece of oil line (copper). There is a small rubber washer on the gauge fitting. Now I have to find one. If this one doesn't work.

 

[puff4]

Yep, that’s the washer that I recall as being installed on them. I would think that a small o-ring would do a proper job if that exact one cannot be found. But again, a gauge repair place should have the right ones.

 

[rixter]

Hi,

I found that the smallest O-ring I had seemed to be a bit bulky in there. My latest idea was to take some rubber tape I have and stamp out the seal size with a couple tubed shaped objects. I used a pipe olive for the outer and a piece of small diameter brass tube for the inside. I've yet to reassemble it, but I hope it works. I have read on other Brit cars forums about there being a seal in this location on similar oil pressure gauges. Bob mentioned earlier about if the connection is real clean a seal may be possible between the two metal surfaces. Perhaps when there is a nick or other non-perfect matching up of the two metal pieces, a thin seal is necessary. Below photos are first with o-ring, then thinner seal made from rubber tape and line fitted to gauge with rubber tape seal.

Rick

 

[65beam]

That "piece of pipe" is part of the fitting of the gauge that seats into the fitting on the line. Check the fitting on the line and you'll see what I'm referring to.

 

[rixter]

When I was saying I felt the o-ring was too bulky, I was thinking that bulkiness would be taking away from the nice fit that the line has to the gauge nipple. A thinner gasket as shown in my middle photo in my last post and the one in billm's post permits some of the protruding pipe on the gauge to get up into the line and still provide a seal. Perhaps a diagram (crude), may help illustrate what I am seeing. In this diagram, what if the metal to metal surfaces indicated with the red arrows are not ideal? How would a proper seal take place without something in there?
Rick

 

[65beam]

When I was saying I felt the o-ring was too bulky, I was thinking that bulkiness would be taking away from the nice fit that the line has to the gauge nipple. A thinner gasket as shown in my middle photo in my last post and the one in billm's post permits some of the protruding pipe on the gauge to get up into the line and still provide a seal. Perhaps a diagram (crude), may help illustrate what I am seeing. In this diagram, what if the metal to metal surfaces indicated with the red arrows are not ideal? How would a proper seal take place without something in there?
Rick

View attachment 19425

You're missing that the gauge fitting is beveled to match the inside of the fitting with the nipple fitting farther down past the bevel in the line fitting.

 

[rixter]

Ahh.. ok. That I will have to look at closer. I did not think there was any taper thing going on there.

Thanks

Rick

 

[65beam]

I'll see if I can get a good photo of the inside of the fitting on the line. I have several NOS lines so the taper should show.