Abstract: A non-convoluted, elongated sealing boot of elastomeric material in, or for use in, a cylinder and piston assembly of a disc brake of a vehicle brake system as a dirt seal to protect the piston and the cylinder chamber from road dirt and to prevent water entry. The sealing boot includes an elongated, molded elastomer sleeve which comprises seven distinct interacting segments, or wall portions, of a plurality of different and tapering thicknesses which permit the sleeve, when installed in a disc brake assembly, to be collapsed to a convoluted shape upon retracting the piston into the cylinder to replace the brake pads of the disc brake assembly.