Replaced my ball joints last year with 555 Senkei since I was using non-OEM lower control arms (my mechanics choice not mine.) Had a look at them a few days ago when changing the oil and filter and it appears both are rusted away with the rubber boot torn. I find it hard to believe both were defective since many people here have used them successfully - so what happened? Did mechanic screw up, or is it possible they did not fit properly with the non-OEM lower control arms?