I just re-did the grease in my TiBook G4, and even though its kinda tight still, its no where near tight enough to cause the broken top case syndrome anymore. I used some white lithium grease, and there are ports that suck grease in (i put new grease in) and push grease out of the bottom port while the hinge is turning. the whole thing rides on a thin grease coating around the hinge pieces. The old grease was like goo and the new white lithium really seemed to clean everything up and make it somewhat smooth again.