How can you check the parking brake holding force on a hydraulic wheel position system?

To check the parking brake holding force on a hydraulic wheel position system effectively, starting the engine and putting it in drive allows the technician to assess whether the parking brake can withstand the force generated by the vehicle's engine. This method applies a realistic load to the system, simulating conditions the parking brake will encounter when the vehicle is under normal operation.

When the engine is running and the vehicle is placed in drive, the vehicle attempts to move forward. If the parking brake is functioning properly, it should prevent the vehicle from moving, demonstrating its holding force. This test effectively evaluates not only the mechanical integrity of the parking brake but also its ability to generate sufficient friction against the wheel to hold the vehicle stationary.

The other methods may not provide an accurate or effective measurement of the parking brake's performance. For example, revving the engine does not apply a load that replicates real-world driving conditions, while simply checking brake pedal feel does not provide objective data on the parking brake's holding capacity. Using a brake testing machine can yield useful insights, but it is not directly correlated to the functional evaluation under normal driving conditions.