https://www.etrailer.com/Accessories-and-Parts/Redline/7-75.html
Today we’re going to review part number 7-75. This is the Brake Mounting Bolt for 7″ and 10″ Brake Assemblies. This bolt is used to attach your brake assembly to your trailer. This is a grade 5 bolt, as you can see it has the three indicator marks, that means a grade 5. The overall length of this bolt from the top of the hex head to the very end is a 11/2″, the threaded portion is going to be a 1 1/4″, the bolt size is 7/16″ diameter by 20 size, the 20 means 20 threads per inch. This needs to be used with the lock washer, part number 5-8.
Note: Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.