automatic braking... wait... my truck is not autonomous!

[dazza]

On my way home from West Coast Natls yesterday doing about 70 when the truck started jumping/bouncing slightly, became much worse by the time I was able to get over two lanes and off to the side. Did a quick look around and found nothing so I thought I'd drive up to the next exit for a better look, although my truck thought otherwise, brake pedal was very stiff and my engine was fighting the brakes. Remembering some issues(more below) from last week, I shut off the engine and then brought her back up which released the brakes and everything was back to normal.
Back up to last week, I noticed a leak from the cap of my reservoir and the rubber seal had been partially sucked in. Cleaned, reseated and closed. After driving the next day, the same thing although a much worse leak (no more por-15 on the frame below). Cleaned everything up, searched, read a bunch regarding the problem, and followed a few peoples idea of making and installing a cork gasket just below the lid. Held up with no leaks, even after the self-applying incident on the way home yesterday.

Not sure what to do at this point, may flush the whole system.

BTW, this is a hydroboost setup.

Any ideas are appreciated.