Power Steering Problem?

Can I get your advice please???

I have a 2003 Silverado Duramax CC 4X4 with about 320,000 km (200,000 miles) and 8,000 hours. I have had it since new. The steering box broke and was replaced under warranty by the dealer when it was a year old. Over it's life the truck developed a few small leaks (attracting dirt) which I was ignoring. Then it progressed to a detectable weep at the hydroboost and on the pressure hoses. It eventually became a leak which required occasional top ups. Last fall it I was out in the bush with it and it leaked down enough that the power steering failed and the pump started howling before I could get to a service station and buy oil.

In December / January I decided to deal with it all at once. I replaced all three hoses, the power steering pump, and the hydro boost. The only thing not changed was the steering box. I used a Cardone pump from rock auto. Since everything was new I didn't flush anything. I just filled it up sparked it up and turned the the wheels left and right to prime.

The pump was too loud and too weak right out of the box and only got worse with time. In February I replaced the pump with a warranty pump from Cardone and this time I primed the system with the truck on stands and no resistance on the steering pump. I thought maybe it would protect the pump if the pump never ran "dry".

So the second Cardone pump lasted a little longer but it has gotten progressively more and more weak and noisy. It needs to be replaced again. The power steering pump howls and shudders both with brake pressure and with power steering demand.

I feel like the Cardone Pump has to be the problem and I am considering putting in an AC Delco pump this time. I just don't want to do this job again!!!

Is there anything else I should be considering? Could the rebuilt hydroboost be causing the issue???
Should I just change the pump and stop worrying?

I do all my own work and I am competent with complex jobs but this is my first power steering work.


Thanks in advance for your advice!

I would stay on the pump, at least until that's resolved. As you said, replacing it improved the condition, only to get worse over time/use. IMO, the pump you replaced was probably better than what replaced it. OEM power steering pumps are remarkably robust, and running them low occasionally or for a little while doesn't usually kill them. Unless you drained out a bunch of metal, it was probably OK. Contamination can damage the hydroboost unit, but a weak pump will hide all but the obvious. Is the power steering effective with the engine running? How many brake applications do you get after engine-off? If the steering is effective and you get 2-3 (engine-off) brake applications, the HB unit is probably OK. Steering power is regulated by the HB unit, while the pump is just a slave to pressure demands. Low fluid can cause pump growling under demand (turning or braking), but still able to produce regulated pressure. Very low fluid will cause pump growl with no load, as it's unable to produce regulated pressure. Just low wont' normally cause damage, while very low can cause damage over time if the pump is allowed to continue growling with no load.

Just a note for future issues, running a power steering pump with ANY type of automotive oil is better than running it dry. ATF or hydraulic oil is preferred, but you can use motor oil, if it's all you have. In dire circumstances, you can use a pint of engine oil (removed from the crankcase) to get you out of a situation. The engine won't miss a pint, and you'll save the power steering/brake system. Of course, it should be properly serviced at your soonest opportunity.