Very hard brake pedal

Hello everyone, I hope and help me, I have a 2004 Cavalier, the brake pedal is very hard, but if it brakes, I was reading around and they say that the problem is possibly the problem, how can I know if the booster is damaged, in other places they also say that it is possibly the empty valve that is in the booster as I can check it?

Possibly you have an empty tube cracked or some lazy clamp and does not make empty in the servofreno, with which you have to step hard to stop, this also happens if an anti -relationship valve of air where this tube is broken is broken (it is less likely). If the vehicle is diesel, it will be necessary to look that the depressor works and makes empty, finally propose that the pulmon of the servofrane is chopped because it has oil (this happens if the depressor is damaged by wear or granted) and throws oil inside the empty tube towards the servofreno. Look to see these things. Greetings!!


** To check the antirretor valve from the servo, disconnect the sleeve and blow into the servo, there should be no air passage, if you aspire to you, you should allow you to enter air, then OK valve.