I have a crack across the glass in my tachometer. How do I get the old glass out so I can have a new one made up? I tried turning the bezel from within the cockpit, and it went counter clockwise (which now looks cockeyed), but won't go clockwise and won't come off. I'm stuck with a cockeyed tach and a cracked glass? Do I have to get the tach out from behind? How do you do this? Thank you in advance for your help.