Well, I didnt either for the longest time. A while back there was a training on moog suspension parts at a local parts store. The moog rep was very committed to the fact the joints must be lined up (line on joint inboard). After pushing the fact, he asked me if it wasnt required why most all ball joints have a mark and indicate the line and boot must be inboard ....I then felt Like an idiot.
His explanation was in regards to the design of the joint and the direction at which it absorbs impact, Turning it the wrong way would equate in less durability and shorter life span. Everyone in the class was shocked, Evidently the insides of the aftermarket moog joints are designed to provide strength according to direction. I never went into any further detail, I already felt like an idiot. So with that said, The mark is there, I guess it makes sense to line it up . In all honesty I dont always line them up, you know, It's already pressed in and I'm not taking it back out. Considering you already had what I would call a premature failure I thought it might be a good idea to try it. One other note is the boot is indexed for another reason, forgot to mention that. The boot has a grease relief and is designed for the vehicle unlike other ball joints (even OEM) the indexed boot improves clearance and uses a grease relief that allows the grease to be expelled away from the brake system. ALWAYS turn the boot correctly, the joint is up to you. Most OEM or TRW joints are not marked so I'm not sure that their design would incorporate improvements that would require indexing

PS if anyone ever get's to go to the Federal mogul classes that are sometime offered at local parts stores you should take the opportunity. The information provided was mainly in regards to the improvements made in parts and their effect on shops. It was a very helpful class, probably more so for anyone involved in parts sales ( i think napa does them sometimes)

Heres the link!
http://www.moogchassistraining.com/

 

thanks for the info. I had my mechanic do the last ones and I am pretty sure he just slapped them in (I was there helping him). IF the upper is worn should I replace the lower also.

 

mite as well y u have it apart be a bitch to do it agian just for lower later on

 

Well I replaced the upper passenger ball joint. All the others are in good condition. Only thing I can figure is my mechanic used a little to much bfh on this one. I rented a press from advance auto and it pressed the thing out and back in with no issues. I even used the steering trick to get the wheel bearing off. Worked like a charm. The old joint was positioned right (mark inboard) so that wasnt the problem. I just hope this one and the others last. Thanks for the help.

 

Moog are probably some of the best replacements around. Stay up on greasing them and you shouldnt have any problems. As stated by Mysterync above, make sure they are installed correctly. There is usually a sheet of paper in the moog box that will give you specific Torque spesc, and installation procedures for each different application of the ball joint.