Boot for slidably guided member

Claim 1

The combination of a disc brake and a boot assembly, said disc brake being of the type having a guided member axially slidable in a bore of a guide member during the application and release of the brake, said boot assembly preventing ingress of dirt or fluid into one end of the bore and comprising a first annular portion sealing against an annular surface of the guide member adjacent to said one end of the bore, a second annular portion sealing against the guided member, and a flexible impermeable web connecting said first and second portions to accommodate relative axial movement of the guided and guide members, wherein said surface of the guide member is a plain surface extending parallel to the axis of said bore and facing outwardly of the guide member, the first annular portion of the boot assembly comprising an annular rigid carrier carrying an elastomeric seal, a first annular part of the seal being permanently secured to a first annular portion of the carrier, and being spaced radially outwardly from said surface of said guide member and a second annular part of the seal spaced axially outwardly relative to the bore from said first part and located internally of the carrier, said second part being trapped between a second annular portion of the carrier and said surface of the guide member to form a seal therebetween, and said second part of the seal being unattached to said second portion of the carrier, the arrangement being such that during assembly of the first portion of the boot assembly onto the guide member by application of an axial force to the carrier member said first part of the seal passes with clearance over said surface, and friction between said second part of the seal and said surface results in axial elongation of said second part of the seal to enable the seal to be pulled into position on said surface by said axial force on the carrier.