Final answer:
The percentage of fifth-wheel mounting bracket to frame fasteners that can be loose or missing before the tractor must be placed out of service is not specified by the Commercial Vehicle Safety Alliance (CVSA). It is necessary to consult the appropriate regulations and guidelines for the specific tractor in question.
Step-by-step explanation:
In order to determine the percentage of fifth-wheel mounting bracket to frame fasteners that can be loose or missing before the tractor must be placed out of service, it is important to refer to the guidelines set by industry standards. According to the Commercial Vehicle Safety Alliance (CVSA), any loose or missing bolts should be tightened or replaced when noticed. However, there isn't a specific percentage provided by the CVSA for the number of fasteners that can be loose or missing before the tractor is placed out of service. It is recommended to consult the specific regulations and guidelines set by the appropriate governing body or maintenance manual for the tractor in question.