OOSC, Part II, Item 4. Driveline/Driveshaft - Shear Bolts

Currently the CVSA OOSC does not address defective driveshaft shear bolts as an issue. Driveshaft shear bolts have been observed on driveshafts during Level 1 CVSA NASI and a times have been documented to be defective by either bolts being loose of missing. Similar to other mounting bolts on the driveshaft (ie. bearing cap bolts, retainer bolt, etc.) if these bolts/nuts were to become loose they could impact the safe operation of the vehicle. The shear bolts are installed to help prevent damage to the driveshaft should there be extensive torque put on the driveshaft. When there is too much torque put on the driveshaft the shear bolts are supposed to break hopefully before there is damage done to the driveshaft or driveline components. I will send some pictures of the driveshaft shear section.

Similar to the mounting hardware for the universal joints at the yokes on the driveline, driveshaft shear bolts could lead to an unsafe condition. If the shear bolts were to become loose or defective in some way during the operation of the vehicle it could result in the driveshaft sections dislodging and can lead to a vehicle’s inability to move and/or drive line parts falling off the vehicle and becoming hazardous road debris and/or airborne. Once a driveline fails, the bus, truck or truck tractor can no longer move and then becomes a road hazard itself.

Could this issue please be reviewed by the Vehicle Committee to see if it would be worth adding driveshaft shear bolt defects (loose, missing, ineffective) to the CVSA OOSC in the Driveline/Driveshaft section.