[Blue Tank]

Hi Guys
05 Burb, 4wd, 5.3 130k
A couple of months ago when it was really cold out one morning i fired up the burb and had a very loud p/s noise. It was real loud. I shut it off for a bit and fired it back up to find it was still there. I let it idle a bit and it sounded a little better, I had to go.
Some days the noise is better and the warmer weather seemed to help. Originally I thought there was probably some water in the fluid and it has frozen the bypass open, that's the sound it makes. It also shows up in the hydro boost when you press the brake pedal. Now that it's warmer that dream went away. When I checked the board I noticed that a couple of guys had a pin hole in the pressure lines. I checked and the pump to hydro line had that fine dust stuck to the covering. Ordered 2 new pressure lines, replaced them today and I think it sounds worse.
I watched the reservoir with the cap off and the truck running, the fluid still has small bubbles after bleeding it. After turning the wheels while up on a jack and then leaving them centered with the motor on it looks like its "simmering" in there. Not continuos but every few seconds decent size bubbles rise up thru the fluid. When you step on the brakes it like all hell breaks loose in the rez. If you touch the pressure lines it feels like they are vibrating at idle.
Any ideas?
thanks
Mark