Instrument overhaul

I was wondering if any companies or people are in the business of overhauling or servicing old instruments which would have no original doc’s or info to go with them. I have a couple of german artificial horizons that would require a service before they were flight ready, one runs very well but I think a check over would be a good idea before it was run for any amount of time; after 60 years of doing nothing it could probably do with a bit of a lube. Another one works fairly well but is in definite need of a service. The turn indicator gyro runs very well but the vertical gyro for the horizon is not doing so well, when caged it was not running but after I uncaged it and it rolled itself round abit it decided to start operating and ran up well but probably to only about 60% of the RPM required, it gave erroneous readings when rolled and pitched in the hand (as the gyro tumbled around), there was no excessive noise etc. but something is not quite right and could do with an experts eye.
Is there anybody out there who would be able to offer any advice?
Thanks
Matt