The trick with the O ring is to put it on/around the shaft/pin that goes through the eyelet, not on the side of the pin....that takes up the slack of the bushing while still allowing full tightening of the pin bolt. When all together , you will then see the bushing can not move sideways b/c it is now sandwiched between the O ring and washer..you can use one on each side.
I have done this to many and they have lasted for years.
Correct way is supposedly a new shock, but O ring trick does work if done right...[ not that you have not done it correctly] and seems to be better than a new shock b/c the new shock seems to have the same fail rate as the old one did....