A ball joint 110 for a vehicle having a housing 120 partly enclosing a ball member 112 a cover member 150 provided by an annular, partially everted body of steel which at one end 158 surrounds the housing for attachment and at the other 156 is in-turned at 160 to approach the spherical surface 118 of the ball member radially and at about 45 degrees to the member housing axis. This other end 156 supports an elastomeric sealing ring 142 biased by the member 150 against the spherical surface to prevent contaminants being carried by the ball to the housing seat 126. To tailor the resilience, the cover member is provided with an array of slots 1681 . . . at the curved region 160 which are filled with plugs 1721 . . . of contaminant excluding elastomer and/or the ball sealing ring is biased against the housing adjacent the seat.