So, I've looked up how to check for ball joint wear, but how much "play" is acceptable for a 95 240SX?

 

...nobody?

 

None is acceptable. If when you have the car off the ground , you can jiggle the wheel because there is play in a ball joint, its done

 

OK, thanks

 

depends on the joint. ball joints that carry a load should have little bit of play in them, ball joints that do not carry a load should have NO play in them.
load carrying ball joints need to have the load taken off for you the check them properly.

i can't tell you which is which on a 240 cuz i dont have one to look at.