If it's the rubbers fixed just above the sill on a chrome runner rather than fixed on the door, I can understand the problem. They look like an arse to do. :grrr
There's no obvious way to see how they're fixed on as they form round a chrome metal runner. The runner is fixed on to the sill but it's only until you've peeled back a lot of the rubber to see how to remove it.
I'm getting bubbling paint and rust as water has gotten behind the runner.