I bought a new car how brakes, so I went to a nearby 4S store, want to let them help me see it, they opened the car, said slack adjuster a little loose, with wrench tighten it, they also gave me a common sense, said if the brake performance is not good words, he put the car cover is open, have a look Is it right? Slack adjuster there is a problem, if it is slack adjuster if you have any problems, just tighten or replace a line, I think that simple so I would not have to come all the way to the car to the 4S store opened, not as good as I practice at home, because it is very convenient, so from then on I seldom go to the 4S store.