I have a 2003 H2 that the power steering went out and even though i replaced it the power steering pump it is hard and brakes make you wonder if your going to stop. Power steering pump was purchased at my local parts store. I was told the pump is the smae as Chec and GMC suv's. Seems noisy as well so I think its the pump again.

 

Who did the install? If it was the dealer maybe you could take it back to them....

 

The power steering pump is heavy duty for 2500 series trucks,because you also have hydro-boost,I don't know about aftermarket,but the pump from HUMMER has been redesigned with a new flow valve.it's possible that your aftermarket pump required you to install the flow valve from the old pump,witch in turn wouldn't help you too much

 

I had that issue... the dealership said it was within limits... and jacked the pressure in my front tires 5psi thinking I would be too stupid to notice...

I changed the fluid and made sure it was full.... my issue went away...

 

We had the same problems with our 2003 and 2005 H2's. The problem is the power steering pump, when this goes out so does your power brakes. Both Hummer's had the pumps changed twice at the dealer under warranty. All is ok for a while but over time it goes out again. I dont think the pump can take powering the steering on a truck that is this heavy. Just my two cents...