Based on what I have found, your 2018 K-Z Durango Gold 5th Wheel more than likely has 7,000 lb axles. I recommend verifying this information to be sure. Assuming that is correct, I recommend the Hydrastar Disc Brake Kit w/ Actuator for Tandem Axle Trailers # HSE7K-T1.
This kit is designed for 7k axles and uses a # 25580 inner and # 14125A outer bearing. The kit includes the disc brakes, Hydrastar actuator, and a brake line kit. Grease caps are available separately. If you want to use... view full answer...