If your old balls are worn out, then it's time to change them.
Instead of stuffing around with replacing races, checking old balls, regreasing old balls, dropping old balls when removing them and taking two hours to find the rotten little buggers, it really is easy to change them to tapered bearings.
Just have all the necessary tools ready and be methodical about the process.
When I replaced mine, I had the triple clamp powdercoated, and this didn't help in pressing the bottom bearing onto the clamp.
Knocking out the old races is simple - screwdriver and hammer from the inside of the steering neck. Just work you way around the race with a couple of hits each time, it won't take long for it to fall out.
The rest is easily done, you may need someone with a hydraulic press to fit the bottom bearing on the triple clamp, don't forget your spacer washer at the bottom either.
Last of all don't forget to pack the grease into those bearings..
Go get dirty...