Power Steering & Power Brakes gone

[dannomatt]

My 2005 LLY sat for 3 or 4 days, and when I started it, I had no power assisted brakes, or steering. I struggled it to the curb and parked it. I searched for an hour for fuses that may apply to brakes and/or steering. - Nothing. No brake fluid leaking, ditto for power steering fluid. I started it to move it to the driveway, and a moment later I heard a click from under the hood, and suddenly my steering and brakes came back. Anybody got any ideas? A friend spoke of a hydraulic pump that the diesels have that provides pressure for power assisted accessories like brakes and steering. The local Chevy dealer (not surprisingly) had zero advice. The truck is moth-balled for the time being, because of the obvious safety concerns.
Ideas?
Anybody - Anybody... Buehler??
Thanks

[DmaxMaverick]

It could be the pump, or hydroboost unit. The "click" was something breaking loose, and allowing fluid flow. They system works without ANY electrical help, or regulation. Completely hydraulic. The hydroboost unit regulates hydraulic power (supplied by the single pump) for itself, and the power steering. It's difficult to say why it did what it did, but a fluid flush does sound in order. I recommend a flush, and replacement with synthetic ATF. The flush is very simple and clean. More on that, if you need it.