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Dvldog8793
12-07-2006, 10:53
Howdy
My step-father has a 2005 2500 HD 4x4 w/ Duramax. He has been having sporadic power steering problems. It was described to me that occasionally the power steering will groan and then the steering becomes very loose or unmanagable. He has said that at times the brakes have been affected also. I have never been in the truck when it happens and the truck has been to a dealer several times and they have not been able to fix it.
Any ideas????
Thanks!
Conley
DmaxMaverick
12-07-2006, 13:54
Sounds like a hydroboost unit OR pump problem. What has the dealer done? Many times, they only look at the pump or gearbox when we have steering problems, and totally discount the HB unit. If they haven't checked/replaced the HB unit, they are probably barking up the wrong tree. If only the steering is effected, it could be either the PS gearbox or pump. If brakes and steering are effected, not at all likely the PS gearbox. What is the condition of the fluid? Level and color? When does the brakes and PS give trouble? What happens and what does the noise sound like?
ramblinrodney
12-12-2006, 18:08
It sounds like its the power steering pump. I retired from delphi the
plant that makes all power steering pumps. The hydroboost is the power
steering pump for your brakes. Thats why you have two return tubes.
Ones for oil return, other for vacuume for your brakes.
DmaxMaverick
12-12-2006, 20:19
It sounds like its the power steering pump. I retired from delphi the
plant that makes all power steering pumps. The hydroboost is the power
steering pump for your brakes. Thats why you have two return tubes.
Ones for oil return, other for vacuume for your brakes.

The HD trucks and all GM Diesels do not have vacuum assist brakes.

Here's how it works....
Pump supplies fluid flow to the hydroboost. The hydroboost regulates the flow to create pressure for brake assist. The hydroboost also regulates the flow to the power steering gearbox. Each, the hydroboost brake assist and the power steering gearbox, have a return line to the pump. The flow/pressure to the steering gear box is regulated by the hydroboost unit. The brake booster also has an accumulater, that little aluminum canister at the top/inboard of the HB unit. The accumulator stores fluid pressure for braking in the absense of pump input, like after the engine is stopped, or if the pump fails. It provides 4-8 brake applications.
Dvldog8793
12-13-2006, 20:04
Howdy
Thanks for the replys...I have been trying to get more info from him and it is sounding like it could be the hydroboost. I've always thought they were fairly bullet-proof???? I think he said that the dealer had replaced the pump and some type of module/modulator. Do the newer trucks have an electric variable rate power steering???
Thanks again!
Conley