I think (the very knowledgeable and highly esteemed) JamesMartin was talking about replacing the axle swivel ball joints... I've not long done the four track rod ends on my wives discovery 300tdi using nothing more than a cheap and relatively nasty "Laser" branded ball joint scissor type ball joint splitter and a nut runner. The ball joint splitter is only £21.99 from Halfrauds, http://www.halfords.com/workshop-tools/tools/hand-tools/laser-ball-joint-separator-scissors and cheaper elsewhere. I used it with a nut runner / impact gun and it worked a treat, I think using the nut runner makes them more effective because as well as exerting torque on the leadscrew therefore the force on the fulcrum, its rattling and vibrating it and effectively emulating you tightening the leadscrew then hitting the side of the hole with a hammer to try and shock it.