Patent ID: 8262173

Claim:
A system for releasing a spring applied parking brake of a disabled vehicle having a service braking system and a spring applied parking brake system with a towing vehicle to facilitate towing comprising: a source of hydraulic fluid, the source of hydraulic fluid being provided in one or more elevated pressure levels at the towing vehicle; means for supplying one of the one or more elevated pressure level hydraulic fluids to the spring applied parking brake system of the disabled vehicle; means for controlling and monitoring the supply of the hydraulic fluid to the disabled vehicle, the controlling and monitoring means located on the towing vehicle so as to control the operation of the spring applied parking brake system on the disabled vehicle from the towing vehicle, wherein the ability of supplying the elevated pressure level hydraulic fluid to the disabled vehicle permitting towing of disabled vehicles with parking brakes systems using an elevated pressure parking brake system hydraulic pressure, wherein a single line between the towing vehicle and the towed vehicle is used for both supply and return of the selected hydraulic fluid applied to the spring applied parking brake system and the braking system of the towing vehicle including a parking brake and a service brake, and further wherein the means for controlling and monitoring the hydraulic fluid controls the operation of the spring applied parking brake system on the disabled vehicle from the towing vehicle independently of the braking system of the towing vehicle.