Smiths (Electric) Oil Pressure Gauge - how to disassemble ?

[JohnboyLandy]

Hi Everyone,

I would like to open up a Smiths electric oil pressure gauge, but I can't figure how to do that. On the back (see pic) there are two brass threaded "bolts" which are the electrical contacts, and to me it seems they need to be undone to remove the gauge mechanism.

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The problem is the "nuts" that can be seen on those bolts don't have enough face surface to get a spanner on to them, so I am guessing the plastic bits into which the nuts seem to be molded ought to undo, but they won't budge.

Has anyone taken these apart that can share some clues please ?

Thanks
John

[cjc_td5]

Hi.
The bezel surround usually has some tabs with corresponding gaps in the gauge body, so that the bezel can be rotated so that the tabs and gaps align, then the bezel and front glass will come off. Either that or bend the tabs up to enable the bezel and glass to be removed.
Chris.

[Fattima]

Those nuts need to come off I would say as that's how the Smiths gauges I have worked on were put together. Can you get a deep socket or tube spanner on them?

[JohnboyLandy]

Those nuts need to come off I would say as that's how the Smiths gauges I have worked on were put together. Can you get a deep socket or tube spanner on them?Thanks guys.

Chris, yeah I have the front off, glass out etc, but I now want to remove the mechanism which is attached to the back.

Fatima, thanks for the suggestion, I don't have any tube spanners, but there's bugger all room around the nuts. I suspect there's a special spanner required.

I'm thinking I could carefully file down the plastic around the nuts the hopefully get a socket on to it.

I'll report back with any success.

Cheers
John

[JohnboyLandy]

I was lucky to have a spare oil pressure gauge to experiment with, so I filled down the plastic (bakelite ?) so I could get a spanner on the nuts, but when turning the nuts, the whole screw post turns, so that's not recommended.

The best I could do was get in from the front like Christ suggested, after taking off the bezel and glass, then the face is in two parts, one part sits on top of the needle, so that comes out easy, then the next part under the needle with the markers on it come out too with a bit of manipulation. Once inside I could clean it up pretty well (I had cork crumbs everywhere), so I decided to not go any further and resisted any attempt to remove the mechanism.

Cheers,
John