Unfortunately things aren’t as easy as they might seem because barometer repair shops are somewhat rare because of the fact there aren’t many barometer owners and there are even fewer that are willing to pay for such a repair. Another negative aspect of getting to repair a barometer is the fact that it costs a pretty penny and not many are willing to spend that much on an antique mercury barometer.

As a bottom line I consider that repairing a barometer requires qualified skill and shouldn’t be done at home under no circumstances. All in all I think you’re better off getting a new digital barometer when the old one brakes but if you’re fond of it you should try locating the nearest barometer repair specialized shop and let those people tinker with it.