Dismantling David Harcourt Oil Pressure Gauge

[John P]

I have a David Harcourt 0-20 PSI oil pressure gauge which I was hoping to use to check if the gauge fitted to my Ulsteroid is reading correctly.

It was an autojumble purchase many years ago and the needle was stuck at around 5 PSI.   With a bit of a struggle I have managed to remove the bezel and the two screws on the back which presumably hold the mechanism in position but I can't see how to strip it down any further.

I presume I need to remove the needle and then take off the face but this looks to run the risk of damaging the very delicate needle.

Curiously the needle has now moved down onto it's stop and, as the glass was loose in the bezel, I suspect this may have been the cause of the stuck needle.

Any suggestions how best to proceed?   Also how would the glass have been held into the bezel?

John.

[Stuart Giles]

It'd be worth checking the guage against a known good gauge at various pressures throughout the range .if the readings are incorrect, you'll need to pull the needle off to have a look at what's happened to the Bourdon tube or mechanism. The needles are fitted on a taper, you can get a special tool, but you can make a simple puller yourself, which pulls the needle off by pressing a miniature forcing bolt on the shaft/spindle, I think the one I made used a 10 BA screw.

[Jeff Taylor]

Hi John,

I bought one of these needle removal tools some time ago but have yet to use it so can't comment on its suitability or effectiveness on a David Harcourt oil gauge.

   

Jeff.