The bubbles have to be coming from somewhere upstream, the tools just creating a vacuum. If it was spongy before there must be a small leak somewhere or a cracked line.Oh, it pulled fluid out like there was no tomorrow, even after adjusting the pressure down. I went through 3 30 oz bottles of fluid and seeing nothing but a stream of bubbles. I used a zip tie at the nipple, the old axle grease trick. Nothing. Maybe I got a lemon.