 Ok, let's forget about the tach cable for now. Since your tach is stuck, the core of the old cable is probably (hopefully) twisted off. The gear in the tach drive head is plastic material and may be stripped also. It may turn with the engine running but slip or stop with a load on it. Unscrew the drive head to check the gear. The tachometer is a drag cup movement, that means it is electro-mechanical. That brass drive that you tried to turn is attached to a magnet that is spun by the tach cable. The problem is the magnet, hour drum worm gear, and frame are ferrous and close enough to rust together. You can not force the brass drive or it will break free from the magnet and then it is junk. That is why I ask if the pointer jumps when you spin the brass drive CW. Yours is stuck, better than the drive turning and pointer not jumping, worth trying to fix in other words. You will have to remove the tachometer from the instrument panel to soak it free. To get it out, looking at the back of the panel remove the screws on the left side gauge pod and wiggle it free, down & toward the front of the tractor. The tachometer, amp gauge & temp gauge will all come out and be inside the pod. The temp gauge is a gas actuated mechanical gauge, careful, do not cut or break the capillary tube or it is junk. The tach movement is mounted in the pod with 2 screws. Unscrew the wick oiler container on the side of the drive if so equipped before loosening the mounting screws. Before you start soaking, screw the container back in to plug the opening but leave the wicking out. The pix is how I soak them free. That is a short piece of hose clamped to the thread on the drive. I use Kroil or PB Blaster penetrate and fill up the hose. Protect the hour drum as the penetrate may soften & ruin it. Soaking free can be hours or weeks. After it has soaked for a couple days stick the square end of your old cable core in the drive and wiggle it back and forth, no force, if it doesn�t move very easily continue soaking. The whole process can be tedious and frustrating, you may get it freed up and still have other issues with it like rusted gearing for the hour drum, broken spinal spring, etc. If you lack time to be patient or get disgusted, I highly recommend contacting Roger Hornbaker by email [email protected]. He restores 300 cluster gauge panels, does superb instrumentation work, and is as nice a guy as you�ll ever deal with. Joe
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