Here is an experience I just had.
Brake pulsing. The faster the speed the worse the brake-down shake.
I knew the right rear pads were worn at an angle so did the service there first.
I was blaming the caliper for being stuck as either the piston or the slides.
The piston was free and the slides were free but noticed one slide was a bit lazy sliding by hand.
Inspected under the rubber boots and found it clean as new no rust or any other situation.
Lubed under the boot just on that slide.
Put the new linings in and reassembled.
Went out for the evening and so far not feeling any brake shake and seems to have a bit better braking.
Need to put more time on the new pads before seeing if the shake was due to the condition found then install new pads on the other side to match.
Seems to show just how sensitive the system can be at times.