I have a 2008 6.7 cummins. And a have a problem with the brakes hissing with no load on them. When I apply the brakes it tends to go away. I read that a hose that has a nylon liner is the problem. Where is this hose located?? Is it on the power steering pump end or the booster end? I hope you guys can help because the hissing is beginning to drive me nuts..