yea I've bought two different tools I wasn't sure about opening the bleeder the valve or not as I didn't want to lose to much. Both the fronts were a peace of cake and I've really been musceling the rears and they hardly even budged. I even took a wrench to the handle of the one trying to get more leverage and still no go I'm going to give the bleeders a shot. Am I going ot have to refill it with new break fluid if I only bleed a little bit out or should I be fine?