Brakes locking up

[Priusron]

While leaving OK city Dec 23 I noticed my rt rear brake smoking. I stopped and checked it out. Made it to the next exit to Walmart parking. After removing the wheel I discovered I could not remove the drum as it was locked on. Working in 24 degree weather it took me 1 1/2 hrs to remove the nuts holding the backing plate on. I had to hold the bolt with needle nose pliers an turn the nut with a wrench as I could not get to the bold head without removing the drum. Upon removal I found the backing plate was fractured into 4 large pieces and several smaller pieces. The brake pads were fried. My DW found a trailer repair place 15 miles away. I zoomed to their location and they had a loaded Dexter backing plate. We used their shop to disassemble my backing plate and found the drum was still good. $300 dollars later and after reassembly we were back on the road. Dynamax as assured me they will reimburse me for my costs.