I found an unexpected problem, on Sunday, after washing the car before its annual road test tomorrow [Wednesday].
I had a brake pad wear out on the front passenger side about three weeks ago. I posted the question here, but at the time I didn't drive the car very much after getting the same answer here that I had in my mind. I mentioned, in the previous post, that the front wheel was quite dirty from brake dust, which was of course the clue to what was happening.
What I hadn't expected, and I only discovered when I washed the car, was the heavy dirtying along the passenger side of the car from the brake pad iron oxide. I had driven the car in the rain just after I noticed the front brakes acting oddly, not for very far, and obviously the wheel spray had deposited a layer of oxide all along the paintwork on the car.
I couldn't believe how rough it was, especially as I put a ceramic finish on the car last spring. I didn't expect that the oxide dust would really lodge on the paint surface. The answer was to use a clay bar and clean the whole passenger side of the car. The drivers side was, and is, perfectly fine and didn't need any attention, but there was some oxide on the lower tailgate on the passenger side.
So, I spent this morning rubbing down the passenger side paintwork with the clay bar, and then putting a fresh coat of polish on the ceramic finish. I am now happy to say that the paint has a nice satin smooth finish - again.
I will be much more particular from now on, checking the brake pad thickness, as I don't want the same thing to happen again.
Pierre3.