I agree with both of the guys above. Find a real bearing house in your area and buy quality sealed high speed bearings. (I'm too old to order them on line, Whatever that is) On Second thought, check with E-replacement parts.
Might want to check the housings first, if they are wallowed, it's over.
Also, blow it out and check for dust and crud. Most of these units are not made to run upside down.
I have done this several times and used a piece of plastic pipe to press the bearing home. Not a tough repair.