The MGA With An Attitude
NOISY SPEEDOMETER or TACHOMETER - ST-105
At 10:49 AM 3/11/2007 -0500, David Irvine wrote:
>"I have a wildly inaccurate speedometer. It indicates around 80 mph when the tach at 3000 rpm suggests about 54 mph, plus the speedo makes a terrible squalling sound, especially in cold weather".
Enough said. Loud squalling noise from speedometer is usually a dry speedometer cable core chattering inside the cable housing. Disconnect the speedo cable from back of instrument. Withdraw the inner rotating cable from the jacket, assuming it will pull out. Oil the cable core well, reinstall it, reconnect the cable to the instrument, and see if the fixes the problem. If so, have a cigar and celebrate Cheap Day. If the problem returns, install a new speedometer cable.
While you have the cable disconnected from the instrument, you can put a few drops of oil into the cable connector on the back of the instrument to lube the input drive spindle. That might help. If the noise is originating inside the instrument, and oil at the back doesn't fix it, then the instrument would need to be opened up to lube the spindle bearings inside.