It could be the premium increases. The cars ESP is set up to work with the brakes the car was homologated with. Add more braking power and then get into a panic braking situation and the pulses sent to the rear brakes may create an over braked situation...... After all disc brakes generally increase the braking depending on the pedal pressure and the pulses sent by the ESP when it gets called into action.Clearly, on average, cars are being used on fewer journeys of late, and it has been pretty wet. And some folks may have snow and salt to deal with... My guess would be there will be a higher likelyhood of various stuff seizing up, on many cars, than we'd usually see, not just drum brakes on those still fitted with them....
A disk conversion is appealing, but out of my price bracket! Also, maybe because I use the car at least every other day, my drums seem fine - so far...
Tell your insurer though - they should give you a discount for 'adding safety'!
I would imagine the brake drums are made from poor material. Perhaps it rusts quickly. Supposition of course.
There is very little to service that will prevent the binding some are experiencing. We can clean or sand the shoes and shoe edges and clean up the inner drum faces but if it’s a poor material it will rust up again almost overnight.
I suspect having lots of play in the handbrake and not applying said handbrake is what most will have to do.
Which in my humble means the set up is simply not fit for purpose.