Lost pwr steering/ brakes 00 2500

Have a 00 2500 6.0L 130206 miles. that the power went out on the brakes and steering. The power steering pump has been replaced. Took it for a drive and the power assist is somewhat there when engine is at a high rpm and moving. At idle and sitting still no power assist. Any ideas

Thanks
George

sounds more like a problem in the hydroboost module. is the system losing fluid anywhere?

No there is no leaks. Could a ther be a bad hose or a clog of some sort

No there is no leaks. Could a ther be a bad hose or a clog of some sort

Air in system maybe?
If lose of both brake and steering check power steering pump pressure.
Post back pressure reading.

I had that happen on the '98 Sub backing out of the shop one wintry morning. Drove it right back in (slowly) and started researching. Checked fluid and it was good. Came in the house and looked at my '98 manual for clues. Found that the pump supplies pressure to the hydro-boost brakes and then to the steering box and returns to the pump. Went back out perplexed. Started it up just to check my mind and it was all good?? Had steering and brakes?? Now what?? Replaced the pump and it's been good for 3 years now.

As "MT" & I said, the pump is the supplier for both brakes and steering on your unit. Air in the system could be a problem from the new pump.

This is a short version for pump bleeding from my '98 manual.

1. Front wheels off the ground.
2. Engine OFF.
3. Turn the wheel all the way to the left and fill the pump to the cold line and leave the cap off.
4. Turn the wheel right to left at least 20-40 times while someone monitors the fluid level. If there is air in the system it may push some of the fluid out of the pump reservoir. Keep the fluid level at the cold mark.
5. After this lower the front wheels to the ground and start the engine. Check the fluid level and put the cap back on. Let the motor idle for 2 mins and see what happens.

If you still have trouble then as "MT" says you need to check pump output pressure and/or make sure the new pump is correct for your vehicle.

I made a device using an old power steering reservoir cap and a handheld vacuum pump(almost any vacuum source can work) and creating a vacuum in the reservoir drew all the air bubbles up and collapsed them, it was a trick I learned when I was a line mechanic about 20 years ago. That and turning lock to lock finished the job faster after working on any power steering job.

Have a 00 2500 6.0L 130206 miles. that the power went out on the brakes and steering. The power steering pump has been replaced. Took it for a drive and the power assist is somewhat there when engine is at a high rpm and moving. At idle and sitting still no power assist. Any ideas

Thanks
George
this was a recall on gm trucks with power assist 2500. gm supplier used recycled metal to manufacture power steering pump shaft. push and pull on pulley if it moves in and out too much need another pump. also must use proper bleed proceedure on this one.