I had a leaky hydroboost. Bought a rebuild kit and changed 2 o-rings. It was very simple and straightforward. Reassembled everything pumped the breaks. A little spongy, no big deal as I was planning on bleading them. Start the truck to look for ps leaks. The break pettle was sucked to the floor and will not return. Turn the truck off and pump the breaks. After 15 pumps the breaks start to come back up. I'm stumped. Any ideas?