A disc brake system comprising a brake piston with an annular groove defined in an outer side wall of said piston disposed to slide within a cylinder. A dust boot seal made of a flexible material having a first end and a second end, the first end engaging an outboard end of the cylinder, the second end engaging the annular groove. A plurality of flexible convolutions provided in the dust boot seal between the first and second ends, and the second end defining one or more slots.