Gauge repair

Has anyone tried to repair the oil pressure and voltmeter gauges? The needles on mine are stuck in what looks like the position they were in for years. The oil pressure needle moves when you shake the gauge, but the voltmeter needle is just stuck. I was going to try to pry the stainless ring off the gauge face but i am afraid of damaging it. These are from my 78.

 

I have taken the face off, but not repaired the internals. You can go around the chrome ring and undo the crimp on the back, then snap it off. Be careful, the gauge glass is thick enough, but the dial face is very thin plastic. The glass is usually stuck to a rubber seal, the gauge face sometimes just falls out when the rest comes off.

 

So it is possible to uncrimp the trim ring. Nwedgar what tool did you use to get the ring off?

 

lynn thanks for the links. I have checked out John Strenk's pages before, but he didn't mention how he removed the faces from the gauges. I will try the screwdriver as you suggested. I guess if I screw up an already broken gauge there's no loss right?

 

Yes, a decent screwdriver works. The crimp won't come all the way undone, you'll still have to pry. When I snapped the cover back on it was easy enough to run the screwdriver around the outside and reset the crimp.

 

I took the glass and the ring off of my voltmeter. The gauge face is riveted on so I will have to get a center punch or a small drill to remove the face

 

The stock gauge? I swear I took my volt and oil gauge faces off without any problems. They both almost fell out if I tipped the gauge over and tapped the bottom.

 

I will get a picture posted when I get home. The gauge face with the scale on it is riveted to a small case that encloses the gauge workings, then that entire assembly goes inside the regular gauge housing. Maybe at some point they started making them different.

 

Wouldn't be a Jeep if they didn't do that.

 

Here's what the gauges look like inside. You can see the rivets that hold the face to the small interior case.

 

I see that now...mine weren't of the same era apparently. They didn't say Stewart-Warner on them.

 

These are out of my 78. I tried searching for the Stewart-Warner part number but not surprisingly they're not in production anymore. I can drill the rivets out but I'm not sure how I'd get them back together.

 

Well you at least won half the battle. I've had some success tinkering with various electrical meters so I think you may have a chance at getting them to work and cleaning them up. There are no user repairable things inside a meter you could fix (unless you were an instrument repairmen) The volt meter could just be stuck and you might try to very gently moving the needle from the bottom, not the pointer. If you get it to move it should return to rest at the low end and be free to move to the upper point. You may be able to test it by just putting 12V across it. I'm not sure if they had external shunts or series resistors. Which means you could smoke it if it's not set up as a stand alone voltmeter.

You can clean the face (very carefully) with a Q tip and something like Windex. Be super cautious because the paint may just flake off or dissolve and that's that. Most meter faces can handle Windex.This has worked for me and you can make an old meter look like new after cleaning up the face and inner glass.

It's worth a try, they're useless as the are now.

Good Luck

 

I don't really know how to explain what's wrong with the voltmeter as it's the only one I've disassembled so far. If I'm correct the gauge works by creating a magnetic field that pulls the needle across the face. My needle seems to be magnetized to the spot where it's at. The needle will move but will always returns to that spot and it feels like it is a magnet that is pulling it there. I don't know if that makes sense, but if anyone knows what would cause that it would help.

 

I did try putting a 9 volt battery across the terminals and the needle did move, so I think if I could find some way to get the needle back to the bottom of the scale it would work.

 

Don't know about this one but some gauges go high when no voltage is applied yet when you turn on the key they go to the correct reading. If you look at this meter, the needle was installed after the face plate was installed. That is the only way it could be done. I would look at it very closely and determine the best way to remove the needle from the shaft without bending something or maybe stabilizing the magnet where it wants to be and moving the needle to zero.

 

It would be delicate work, but if you had a block of something hard, like steel, that had a hole in it just slightly larger than the rivet, you could maybe drive the rivet out. Then reuse the rivet by setting it again, when you're ready to reassemble. I'm sure rivets like that are available somewhere, but I think it's worth a try to reuse the rivets.

First you need to remove the needle though.

Yes, I expect it's a galvanometer http://en.wikipedia.org/wiki/Voltmeter - maybe it was connected backwards and damaged, or the field magnet came loose and shifted.

 

I'm thinking that the magnet has probably shifted. The gauge incorporates a Zener diode to make the scale start at 10 volts so think if it had been connected backwards it would have damaged the diode and the meter wouldn't work at all. As for the rivets, had a friend replace a similar rivet on an aviation headset. It was bigger of course but he should be able to tell me how to replace them if I can't reuse the old ones.