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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 15133
Experience:  GM Grand Master Technician 2007. 14 years experience.
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I have a 1998 GMC Suburban diesel that has an intermittent

Customer Question

I have a 1998 GMC Suburban diesel that has an intermittent problem. When slowing down or decelerating, the brake pedal goes to the floor and lose the power steering as well like the engine has stalled. Once the truck rolls to a stop or use the emergency brake to stop, the engine is running and then everything is seems to be O.K. No codes are being pulled and no dashlights come on. It happens hit or miss, sometimes a couple of times in a day or once every few days. One dealer and one other mechanic can't figure it out. Of course, the dealer mechanic has test drive it many times and it does not act up! Thoughts? FYI, I have recently in the past couple of months had the Injector pump changed out and the vacuum pump, as well as the PMD. Thanks, Dave
JA: When was the fluid last checked? Have you heard any whining noises while turning the wheel?
Customer: Are you talking the power steering fluid? Not sure, but I haven't heard any whining noises, but I must admit, my wife usually drives this vehicle
JA: No. I'm the Chevy Mechanic's Assistant. What is the model of your '98 Chevy?
Customer: It's a GMC Suburban with the diesel engine
JA: Are you hoping to fix this yourself? What have you tried so far?
Customer: I have not as I don't have a clue and as I mentioned above, two local mechanics don't know either.
JA: Anything else you think the mechanic should know?
Customer: Not really, except that the computer plug was found not fully seated a while back when the A/C fan motor was changed out a while back.
Submitted: 2 months ago.
Category: Chevy
Expert:  Ryan Schott replied 2 months ago.

sounds like air in the power steering system or a bad accumulator on your hydroboost, I think they service those older ones as a new hydroboost assembly. It could be a bad pump too though, you might pull your belt and make sure you dont have a broken power steering pump shaft, sometimes they split sideways and will sometimes hook up and sometimes freewheel, just make sure your pulley doesn't have excessive in and out play.