Technical SW Fuel pressure gauge question.

I've got an older S/W fuel pressure gauge that has the needle on the wrong side of the pin. I have no idea how it got that way; was in a box with other gauges. This happens to be of the 2 5/8 variety. Is it reparable?

 

The pointer is simply pressed on the center pivot. If you remove the bezel and glass, you can pull the pointer needle straight up and off and then press it back on the center stub on the correct side of the stop post.
You can also try gently lifting the outer tip up and over the 'stop' to the other side, but that way risks leaving a bend in the pointer needle or possibly flexing and cracking off the old paint.

 

Unless the movement is broken .

 

Could a magnet attract the hand high enough to allow it to be moved past the pin?

 

I wonder if someone got the airline off a 125psi compressor to 'test' it

 

Suck on it and see if it goes backwards

 

The bourdon tube inside may have been over-pressurized, causing the needle to go past it's range., and bending the adjuster inside. These have a tiny rack and pinion set up, and they can be adjusted, but it will need dismantling.
If you want to know how to repair it, I will show you how it's done, but it is a lot of stuff to type out here! You will need a good working gauge and a regulated air supply, at least.
Don't just remove the pointer and put it back on the other side of the stop, then use it, you will find (at best ) the indicated pressure is way out, or (at worst) you rupture the bourdon tube.

 

This tickled me for some reason.
I'll probably use it, if that's ok...

 

Its been Over pressured

 

My thoughts were that it got incorrectly "tested" at some point in it's life. The needle doesn't move freely, so it's not "broken" but obviously it's hurt. Hopefully fixable, but hurt. If the tube turns out to be ruptured, is it repairable, or is it now an ornament?

 

Call John Wolf &Co. Been doing gauge repair for decades. In Cleveland 440-942-0083. If too expensive, get another.

 

Did you try smacking the gauge face down, against the palm of your hand to see if you could jar the pointer back to the other side of the pin? Kind of a hack thing to do, I know, but the first thing I would try.

 

The bourdon tube is made of brass, and can be soft soldered if it has a hole. Usually if it has copped an over pressure situation they will let go at the seam. They can sometimes be re-bent back and soldered, depending how badly damaged it is.

 

For starters, the bezel looks like it's toast, so you may as well do what you can to get it off & start from there. Try to save the glass, though, if it's not too scratched. Those gauges & parts are getting harder & harder to find. If it's something simple, you might be able to source a decent bezel, press it on, and you have a good gauge. You should be able to apply some gentle lift to the end of the pointer & lift it over the post. You'll know it if it's feasible ...some posts are higher than others. I know I've done it, but I can't remember what the particular situation was. Removing the pointer in an old gauge is always a crap shoot, so I'd only try that as a last resort. Once you have the bezel & glass off, the guts can be removed in a jiffy for inspection. The "suck test" might very well enable you to verify whether there's a hole in the Bourdon tube. Since you only have 10 PSI going, you don't need a lot of vacuum or pressure to move the needle. Did you try it? BTW, I've actually just used a dab of JB Weld to patch a tube, which worked. I was cutting through a pressure gauge cup, because the bezel was frozen, and I grazed the Bourdon tube with the cutting disc & opened a tiny hole. Let us know how you made out. I'm betting that the gauge works fine.

Also, as a side note, I recently read that John Wolf had a stroke fairly recently, which might have some bearing on whether he's still doing gauge repair. Does anyone know for sure? I never sent anything to him, but I always heard good reports.

 

Is the range suitable for your application? Is it rare? Looks toasty.

 

Those gauge bezels were pressed in very tightly from the factory, so if there was not way for the environment to permeate the inner space, the bezel could look like shit & the face & needle could look great. They aren't rare, but are hard to find, especially in nice shape. For example, I just sold a nice on for $200. Save the old gauges.

 

Here's the complete pic of said gauge. It's not all that bad - the close up made it look far worse. I haven't tried anything as of yet with regards to seeing if it would move in reverse or trying to open it; weighing options as it were. I have far other pressing things to attend to than an ill gauge, but this is on my list of things to look into at some point. thanks to all who weighed in.