OOSC, Part II, Item 1. Brakes, e. Parking Brake (Hydraulic Brakes)

In recent months two of our trucks were stopped for Level I inspections. The officers used the park brake inspection procedures outlined in an April 27, 2016, Inspection Bulletin. The inspection process calls for the inspector to ask the driver to apply the parking brake and attempt to move the vehicle in low forward gear without applying the throttle. According to the bulletin, the vehicle should not move. This process is extremely problematic for several reasons. The forces against the park brake system used in this process can vary from situation to situation. Wheel end forces are dependent upon how the idle is set on the vehicle, the type and size of the vehicle engine, the gear ratios in the transmission, and the gear ratios in the rear-end. FMCSA Standard 393.41 does not provide any performance testing of the park brake system with the truck running and the vehicle in gear. Nor does the CVSA Out-of-Service criteria provide a performance standard with the truck running and the vehicle in gear.

Our company was issued separate out-of-service orders because on two occasions our trucks failed to meet the Inspection test listed in the April 27, 2016 inspection bulletin. If this test is going to be used to determine compliance with FMCSA part 393.41 there must be a means to ensure the forces created during this test do not exceed the forces of a parked vehicle even under the most extreme condition of grade and load. I feel that that there are far too many variables that could prove that this test is not a reliable test of the park brake system. This process is also capable of causing damage to motor vehicles.

There should be a recall of this testing process so that FMCSA inspectors are not using it to determine compliance with the park brake requirements of Part 393.41 or confusing it as a new Out-of-Service criteria.