Lrdchaos

I apologize if this is in the wrong location. I have a Giant tcr with Ultegra 8000 hydraulic disc brakes. The front brake is dragging a little, it’s a little slow to release when I let off the lever. It appears that the piston that pushes the brake pads together doesn’t reset all the way. Can I squirt the entire bare caliber and pad with brake cleaner to see if it releases? Or what is the best fix?

Shinkers

I've never actually cleaned my pistons, but something that I've done when this happens is pull out my pads and reset the pistons with a plastic tire lever. Push them both in all of the way, then put the pads back in and realign your caliper (if it needs it).

This has also been a sign for me that my pads are getting worn and the pistons are sitting out too far.

NoWhammies

I agree with Shinkers I do pretty much the same thing. Sometimes what I'll do, before pushing the pistons back in, is spray them down with rubbing alcohol. I will then thread a shop towel through the housing to clean out the break dust. After a couple of minutes letting the alcohol evaporate, I'll push the calibers back in with the plastic tyre lever.