I am not sure about them being permanently sealed. I just sprayed wd-40 directly on the ball joints. It soaked into the metal and the squeaking and groaning stopped.
1987 mercedes 300E
1995 e320 conversion(hated the 300e grill)
Monochromatic Paint (Custom Blue)
Flat Badged (front)
custom "carbon fiber" console
18 inch HP EVO rims
Sold! Now I drive a Monte Carlo SS