Just took my Cobra for a test drive, 20 miles with moderate up and down grades..........everything’s cool! A month ago, I blew a tire ( my bad, the great looking tire was actually 20 years old). Bought 6 ply trailer tires rated for 50 psi ( original tires were 3 ply rated at 35 psi). Next time out, I had hot brakes......really hot right brake after an hour of down hill towing. I have seen this before on another Cobra trailer. My surge damper checks OK, I believe the surge brake is holding more or less constant trailer braking during extended down grade towing. This causes hot brakes! Hot brakes cause bearing failure!
My fix consisted of new tires, new right wheel bearing and locking out the surge break for extended down hill towing. My F-150 has plenty breaking power for a 1600# trailer..........I may just leave the brakes locked out all the time. All I want and need is reliable, trouble free towing!
JJ