Hey guys i have a question for you, i just put a new rear on my car. I had drum brakes and now i have rear discs. I changed the prop. valve and i bled the brakes. Now when i apply the brakes when driving, i can feel the back brakes grab sometimes, and then other times, there not grabbing at all. Does this mean that i did not bleed the system right or what?? Thanks for any help.