On a properly functioning proportioning valve, if it slides to one side it will re-center itself during the brake bleeding process using simple brake pedal pressure.

Learn the basics behind proportioning valves so you can figure out which 1 would be best for your disc brake system. - Lowrider Magazine ...

Read the Chevy High-Peformance technical article on installing and tuning a brake proportioning valve, brought to you by the experts at Chevy High Performance Magazine.