The Dexter Nev-R-Adjust Electric Trailer Brake Kit # K23-478-479 are 10" diameter brakes for a 4,400lb axle that uses 4 bolts to mount to the axle. These brakes do have a unique mounting pattern of 2-7/8" bolt center spread on the top mounting bolts, and 3-1/4" bolt center spread on the bottom bolts. They are separated vertically with a 3" bolt center spread. This will fit the 4,400LB Dexter axles under your 2013 Prime Time Tracer 3150BHD.
Be sure to get some Deka Heat Shrink Butt Connectors... view full answer...