Toms Bronco Parts is proud to present our New 31 Spline Rear Axles for 66-75 Broncos with a 9" Rear Axle and Big Bearing (3 1/8" O.D.), 11" Drum Brakes. Axles come with wheel studs, Set 20 Bearings and seals and retainer plates. These axles fit 66-75 Bronco's with 3 1/8 diameter bearings and 1/2'' retainer bolts and 11 drums. These axles are heat inducted and have rolled splines for hard core use. The set 20 Bearing is lubricated by the differential gear oil for extended bearing life and heavy load capacity. Drum measurements are made from the inside of the drum.