A method of adjusting a lever actuated bicycle hydraulic disc brake master cylinder. The disc brake master cylinder has a housing defining a cylinder having first and second ends and a port communicating with a fluid reservoir between the first and second ends. A piston is received in the cylinder and the piston has a seal having a leading seal edge between the piston and the cylinder. The lever is operatively associated with the piston to move the piston from an unactuated position with the leading seal edge a select distance between the port and the first end of the cylinder to an actuated position between the port and the second end of the cylinder. The method of adjusting the lever actuated bicycle hydraulic disc brake master cylinder comprises varying the select distance between the port and leading edge of the seal with the piston in the unactuated position and providing a stop preventing the leading edge of the seal from moving between the port and the second end of the seal as a result of varying the select distance between the port and the leading edge of the seal with the piston in the unactuated position.