After installing it and bleeding the brakes push the pedal and set it. After you have it set try to push the pedal again and see if it is rock hard. Then let go of the button and set it without pumping the pedal to see if it will allow you to put pressure in the system after its set. This has been talked about before on here and got a lot of mixed answers. Mine won't let me put pressure in the system if I set the LL and then try to put pressure in the system. I have to set the brake first and then set the LL for it to work.