SAE J1729:2019 pdf free

SAE J1729:2019 pdf free.Parking Brake Drawbar Pull Test Procedure – Truck and Bus
For vehicles with a parking brake system that utilizes friction elements of the service brake system, the lining temperature just prior to any parking brake test must be between 65 °C and 95 °C (150°F and 200°F). Temperature condition the lining material by conducting brake snubs from 64 to 32 km/h (40 to 20 mph) speed at 3 m/s2 (10 ft/s?) deceleration at 1.6 km (1 mile) intervals (If speed or deceleration is not attainable, run at maximum speed or deceleration).
For hydraulic vehicles with a parking brake system that does not utilize the service brakes, the lining material temperature just prior to any parking brake test shall not be more than 65 °C (150 °F) (when the temperature of components on both ends of an axle are averaged or the temperature of the driveline type parking brake material). Temperature condition the lining material per the vehicle manufacturers recommendation but not to exceed the 65 °C (150 °F) requirement per FMVSS 105.
Apply and hold service brakes with 667 N (1 50 Ibf) force. Apply parking brake(s). Release service brakes after parking brake control is at the fully applied position. Hydraulic brake vehicles with a GVWR >4536 kg (10000 pounds) apply up to a maximum of 667 N (150 pounds) to the park brake foot control or 556 N (125 pounds) to the hand control parking brake. If the vehicle does not remain stationary, reapplication of the service brakes to hold the vehicle stationary, with reapplication of the force to the parking brake control at the level specified as appropriate for the vehicle being tested may be used twice to attain a stationary position per FMVSS 105.
For variable input systems, record the minimum applied effort or pressure to lock the braked wheels. For fixed input systems, record the applied effort or pressure and observe if the braked wheels are rolling or locked.Observe vehicle performance whether brake locks and wheel slides, etc. If the system is a cable or rod actuated service brake, allow vehicle to roll between each reading as noted in 5.15. SAE J1729 pdf free download.