Pwr Steering, hyrdoboost, and antilock brakes

Discussion in 'General Chevy & GM Tech Questions' started by HP2, Aug 19, 2014.

  1. HP2

    HP2 New Member

    I've got an '04 1500 with around 140k on the clock and it recently started making the old familiar power steering whine and was getting difficult to turn on tight, low speed turns. Stepping on the brakes made it worse. So I replaced the PS pump. It seemed to improve everything and the last few month it has felt better but it has slowly starting to make the same whine again, but now when using the brakes and performing tight steering moves it is more pronounced than before the pump replacement.

    I did use an aftermarket rebuilt PS pump and I do know that you can occasionally get a bad rebuild. However, I'm surprised it would fail within a few months. When it was relaced, I di dnot notice anything unusualy with teh fluid that came out of it. It didn't smell burned, wasn't black, or anything out of the norm. I did try purging the pump and steering box with Sea Foam wondering if I had a sticky valve. New fluid was put in with no apparent change.

    So my question is, do I have a bad pump again or is there some other component contributing to the problem by placing excessive demand on the PS pump?
  2. Pikey

    Pikey Moderator Staff Member 5+ Years ROTM Winner 5000 Posts

    Most autopart stores and rebuilders do not realize that there is a difference between pumps for a non hydroboost truck and a hydroboost truck. I had the same issue, installed the correct ac delco pump and the problem was solved. There was a recall on your model year for a cracked valve inside the hydroboost unit. The GM Document ID# 1528250 explains the issue.
  3. jmcover

    jmcover Rockstar

    What fluid are you using? I remember watching a hydroboost video that warned about PS fluid foaming and needed an additive.
  4. Pikey

    Pikey Moderator Staff Member 5+ Years ROTM Winner 5000 Posts

    I use regular ps fluid. When installing the pump it came with directions that said to turn the wheel lock to lock 30 times after filling the reservoir and before starting the truck. This moved fluid thru the system and I had no foaming at start up after install. I have never had an issue with the fluid foaming during operation.
  5. HP2

    HP2 New Member

    I likewise have only used regular power steering fluid without additives. I have not noticed any foaming during this replacement nor anytime after. I could see where foaming fluid could cause issues within the system.

    Thanks for the info on the document ID number. I'd say its worth calling the local dealer to see if this was ever updated on my vehicle.
  6. HP2

    HP2 New Member

    Okay, called a local dealer to lookup the valve bore recall. My VIN was outside the specified list, so I'm clear there. Next step was to pull up my receipt for the replacement pump. I looked up the part number at the vendors website and think I may have found the issue. The part number they gave me says it is not for vehicles with code Y91 luxury package or BPH off road package. I don't recall the counter guy asking me those questions When I did check the BPH package, which I have, the required part number was different. So I assume this is the hydro boost difference Pikey spoke of.

    So I went to the store, explained the situation, and they agreed to swap it for the correct pump. However they didn't have it in stock and needed to order it, which might explain why I was given the incorrect pump previously. It finally arrived yesterday and I got it installed. Wow, what a difference! It actually powers the steering and brakes both at the sometime. Parallel parking was a chore with the brakes and steering being used and it is now a breeze. A long 1 mile steep downhill road no longer makes the pedal kick back and vibrate.

    So I'm optimistic that with the correct pump, this issue may be closed for me.

    Now to deal with those squeaking brakes...
  7. Pikey

    Pikey Moderator Staff Member 5+ Years ROTM Winner 5000 Posts

    glad you got it fixed

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