The tube in your gauges that guides the light beam to the lenses is often dried and need to be replaced.
There is kind of 'chicane' in the tube and you cannot use a straight tube for it.
I have produced my own ones, by making a mold and using heat shrink. I made the mold of epoxy resin. I closed one side of the original tube with tape and poured some epoxy resin in it. After a couple of hours, the resin had been cured and I was able to get the mold out of the tube.
I have used a heat shrink tube of 1", put the mold in it and after heating it up, the heat shrink got the shape of the mold. I only had to cut of the rest of the heat shrink and ready!
See pictures:
The original tube and the mold:
The mold in the heat shrink
The heat shrink after heating
The result next to the original tube. It is not exactly the same, but the dimensions are correct. The tube is not visible after closing the gauges.
