WARNING: This page is about a different car, the 2008 Suzuki Swift +, 2008 Pontiac Wave, and 2008 Chevrolet Aveo. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: View Of Master Cylinder Body Valves
Courtesy of GENERAL MOTORS CORP.
Disconnect the brake lines from the proportioning valves.