Please bear with me, as I am very new to bicycle maintenance.
I changed the brake pads in my front brake (Tektro Auriga on a Rockrider 540 bicycle), as I was unhappy with the braking performance and couldn't seem to improve it. It came with E10.11 brake pads and I changed them to P20.11 ones. (It should have come with A10.11, but that's not what I found ...) These had much better reviews on Amazon, with many people saying that the braking performance is noticeably better.
Unfortunately, now there is screeching and pulsating when using the brakes. What can I do to improve this?
I am certain that I did not contaminate the pads. I was very careful when changing them.
When changing the pads, I cleaned the rotors thoroughly with 70% propanol.
I performed the bedding-in procedure as instructed: Speed up as much as I can, then brake hard, but do not stop. Do it at least 10 times. I used some water on the brakes before bedding in, as suggested in this Park Tool video.
Strangely, if I pour some water over the brakes, then they become smoother and the screeching disappears for up to an hour. After that, everything is back to how it was.
After changing the pads, and for a second time after bedding in, I adjusted the brake calipers by loosening the screws, pulling on the brake lever and tightening the screws. The rotor looks parallel to the pads. The rotor is true, as far as I can tell.
I am quite disappointed about the outcome of this experiment in changing brake pads, and I would appreciate any advice on how to get rid of the pulsating, if not the screeching.
The only advice I could find on how to deal with this was to lightly sand the rotors, as well as the pads. I am somewhat reluctant to do that after reading that this could worsen the pulsating. I do not have the tool to remove the rotor, and I am worried that I could not do the sanding well enough while the rotor is on the wheel.