Instruments may only be repaired/overhauled by FAA certificated instrument repairmen. A and P mechanics/ IA's have had their certificates suspended or revoked by the FAA for doing instruments repairs as simple as adding fluid to a compass. While it may be simple and inexpensive to repair your own instruments it is illegal.

Tim A&P, IA

where does one get the barrings and associated parts to rebuild these yourself?

Second question is, is this a wise thing to do if one only flys vfr? Not that vfr into IMC never happens and the instruments become more critical.

soaringhiggy wrote:where does one get the barrings and associated parts to rebuild these yourself?

To be legal in a standard airworthiness plane, it does need to be done by a repair station. That being said, the process is similar in difficulty to an owner packing their own wheel bearings or changing a tube and tire after you have tried it a couple of times. So consider the task "for educational purposes only" with all the usual boilerplate legal trimmings.

You can get the bearings themselves from a number of sources like Boca, VMC, and the usual places like Mcmaster. The bearing numbers are etched into the sides of your existing bearings unless they are older than the 60's or 70's, in which case simple caliper measurements can be taken to make appropriate choices, along with ball counts, from a bearing catalog. You take yours apart, write down the bearing numbers or ball counts and dimensions, and you'll have new ones in the mail within a week or so.

I recommend using ABEC-7 or higher. They cost twice as much but they run much, much quieter than the ABEC-4 or -5 junk the certified service stations often jam into your $600-$800 rebuilds that last a few to several hundred hours before those shops see their handiwork back in their shop.

If your gyros are slow now, the first thing to do is check to see if the case has a built in screw-in sintered filter to replace. It can fix the problem pretty much by itself if they had significant buildups on them. Many old certified installs didn't bother with a central filter for the vac instruments. They come in two basic sizes, and you can find them at Mcmaster and on ebay. A set of dental pics, good jeweler drivers, and a miniature circlip plier kit are helpful. So is doing everything in a workspace to contain small bits that go flying off into space. I used electronics cleaner sprays for getting thing spotless. It can take a bit of it to flush the air paths. Small flat colors from the hobby store to touch up. Xacto knives to take the bezel and glass off, and some black silicone to put some of them back together.

For electrics, the process is a bit more time consuming as things are really packed in there and sometimes require a small puller or an arbor press to finish the job.