Posted by David Sherman on Thursday, December 15, 2005 at 3:53PM :
In Reply to: Re: Speaking of speedos.. posted by David Sherman on Wednesday, December 14, 2005 at 6:41PM :
I don't know about yours but on most of them, the metal top or trim ring is rolled over around a flange on the front of a metal or plastic housing. You have to work around it with a small screwdriver, prying up the rolled-over part until it comes apart. Yes, it bungs up the rolled-over part, but if you do it neatly, the bunged-up part won't show from the front. Once you get it apart, you can touch up any peeled paint by hand using a fine model brush, glue a loose needle to its post with super-glue, straighten a bent needle, solder or glue a broken one or even try to make a new one, etc. The needle has to be extremely light. If the speedo was sticky, there probably some magnetic dirt in around the cup (an amazing amount of dirt turns out to be magnetic, given a chance). You can use various careful methods to clean it out. It's also possible dirt might have gotten into the pivots. The main thing is not to damage the hair-springs, so be real careful if you try to blow dirt out with compressed air. If you don't damage or move the hair-springs, and the magnet hasn't lost its strength, the calibration should still be okay. Once it's all done and you're sure there's no dirt in it, put it back together and bend the cover trim back over the housing flange to hold it in place. If there used to be a rubber gasket in there, you might want to run a bead of non-corrosive silicone ("sensor-safe") around the edge to keep moisture out. You won't be able to roll the trim onto the housing properly without the machine to do it, but you can bend it over well enough by hand with a light hammer and a small drift or punch. Set the speedo face down on a solid table with a cloth on it. I've taken apart and fixed quite a few gages of all kinds and have been happy with how they've all turned out, given that the alternative was to junk it and buy a new one.