Dig Posted April 3, 2017 Share Posted April 3, 2017 Thanks to everyone that responded to my post on speedometer removal. I successfully removed the speedometer, took it apart, cleaned all the old hardened grease, and reassembled it. I also replaced the cable. The good news is that I now have a functioning speedometer, bad news is the speedometer reads 20 mph, and the speedometer app on my phone says I'm going 32 mph. Since the speedometer wasn't working when I got the car, I have no way of knowing if it was accurate before it stopped working. I was wondering if I did something while I had it apart to cause the problem, or maybe, and I doubt it, the speedo gear in the trans is incorrect. Since I'm now pretty good at removing, and replacing the speedometer, how do I calibrate it? I read somewhere it may have something to do with demagnetizing the magnet when I had it apart. As usual, any and all help is much appreciated. Link to comment Share on other sites More sharing options...
Bloo Posted April 3, 2017 Share Posted April 3, 2017 The first thing to do is to check if the gearing is ok. Gearing is a separate issue from speedometer calibration. Take it out and drive it 10 miles, while paying close attention odometer and to the mile makers. If you gained a tenth, the speedometer is geared 1% fast. If it gains a mile, thats 10% fast, etc. Gearing is fixed with the little set of speedometer drive gears in the transmission. The steps (for different gears) are usually around 5%. A different tire size can also make a correction. If the speeedometer still reads wrong, then it needs calibration. You could drive 60mph (one mile a minute) by the speedometer for 10 miles, and have a passenger time you with a stopwatch. It should be exactly 10 minutes. You can caluclate how much change you need to make from there. I don't know about the magnet. I usually get the gearing right and let a speedometer shop calibrate the head if it needs it (it usually doesnt). Link to comment Share on other sites More sharing options...
Dig Posted April 30, 2017 Author Share Posted April 30, 2017 Thanks for the reply Link to comment Share on other sites More sharing options...
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