How do you tell if the power steering pump is KAPUT?
 

Recently I had to replace the power steering hoses on my 1995 E420. This car always felt solid on all four wheels and was probably the best handling car I've ever had.

When I got it back from the shop the steering is not as precise as it was and I now have to thing about the car's tracking as the "feel" is not there anymore.

The only thing I can think of is that when the leak developed I had to drive around five to ten miles with very low PS fluid...could that have damaged it?

Anyone come across this ?

Thanks in advance for your inputs.

Can you elaborate on what "feeling" you're missing? The Power-Steering affects the ease that you can turn the wheel. Is the steering wheel now "heavy" feeling? Or is it too light and over-assisted? If the latter, you probably had problems long enough that you didn't notice the lack of assist.

I don't think a worn pump would give the feeling you are (I think) describing. It sounds more like worn tie rod ends. When my tie rod ends were worn the car would follow ruts in the road. That is the basic symptom I use to diagnose that.

Was the PS pump buzzing when low on fluid? Is it buzzing now?

Generally, it takes thousands of low fluid miles to do any real damage, and even then, it will just get noisy rather than lose much output pressure. The first signs of real damage would be buzzing / hard steering when the engine is idling and car stopped. This is because the pump is capable of less volume at idle but the steering gear needs more pressure.

If you were driving without any fluid pre repair, the steering would be stiff when stopped and heavy while rolling.

The system probably has lots of air in it from the hose change giving assist , no assist. There are all sorts of brand specific procedures but the easiest one is to drive car, let sit for a few hours or more for bubbles to rise to the top then drive again. In other words, drive it a few days, check fluid once in a while and report back.

To answer Diesel's question...after driving again today, the feeling is that the steering is not returning to neutral after any turn. It has to be brought back. And that never happened before.

The steering box in my ancient air cooled VWs used to do that, but they were adjustable. Now I'm wondering if one of those mechanics fiddled with it.

That sounds more like alignment or suspension problems. If the power steering system were in trouble the steering would be very hard to turn, but it should still self-return, even if the pump weren't working. The self-centering of the steering is a function of alignment and suspension geometry.

When the power steering is completely kaput, the car drives like an old 3-ton truck built before 1950. Those were pre-power steering trucks, and you could not turn the steering wheel when the truck was not moving. Training on driving those trucks devoted substantial time on positioning the front wheels when you were trying to maneuver the truck; the wheels had to be positioned while the truck was still moving. Generally, the driver position the wheels in the direction he next intended to go before the truck was stopped. (I got my instruction with these trucks when I was a counselor at a Boy Scout camp and when I was in the Army.)

My experience with kaput power steering on my car ( a '98 e 300) happened in early August when the serpentine belt jumped its pulleys and tracks and wasn't turning anything. This happened about a half mile from my home, and I drove the car home where I could work on it. I could not turn the wheels when the car was sitting still; I could turn them with some difficulty when the car was moving. I was able to get the car home but had to make a really wide turn to get it into my driveway, because the usual turn was not possible.

Several months ago, my power steering pump failed. I discovered it failed when I looked under the hood to see where the screeching was coming from. I drove home at that time. The steering was fairly good even thought the system had lost a considerable amount of its fluid.

I ordered parts from here,and rebuilt my pump on the car.Never removed it,just pullled the guts out,and took off belt.I ordered new filter too.