691 Brake Lock Systems

691 Brake Lock Sytems automates hydraulic braking pressure in the service brakes to supplement the vehicle's mechanical parking brake and provide extra holding in heavy-duty and high-frequency applications. The 691 Brake Lock significantly enhances vehicle holding capability while not interfering with normal service brake function.

The ZF 691 Brake Lock can be interlocked with other vehicle components/systems such as a power takeoff control, bus door or wheelchair lift to insure the brakes are locked whenever those components/systems are being utilized.


  • Automatically monitors and maintains optimal brake lock system pressure
  • Provides ability to lock up to four channels using seperate actuators
  • Can be controlled remotely
  • Activates by the flip of a switch
  • Can be diagnosed using LED's
  • Comes with waterproof control module and weather proof connectors


Related Product Information

691 Electrohydraulic Brake Lock System (Form Number 80-690-001)

This 4-color brochure introduces the 691 Brake Lock System and focuses on the individual 691 components. Features, benefits, dimensional drawings, and basic operation instructions are also included.

81-690-032 690/691 Brake Lock Manual (Form Number 81-690-032)

This 24-page service manual includes installation, operating, and trouble shooting information. Coded wiring diagrams and a specific 691 Models/Replacement Parts Table are also included.

ZF Off-Highway Product Guide (Form Number 80-950-006)

This is our introductory catalog for ZF Off-Highway Solutions Minnesota Inc. products. It provides product photos and brief descriptions of the product portfolio offerings in brakes, brake actuation, valves, and controls.