Wow, bummer replacing the rack and it was not the problem. I replaced a rack once on a Ford Probe and it was not something I want to do again anytime soon.

Anyway, I have been thinking my power steering pump is kaput because it is making a whining noise. I put some Lucas Power Steering additive in and it has quieted down the noise considerably but not all together. I was thinking a new pump is in order but your post has me thinking that it could be the reservoir and not the pump. Tonight the hose to the radiator popped out causing fluid to leak all over the road with no power steering on the way home. This could be due to the thicker Lucas fluid when it is 14 degrees F out today.

I have a 1999 ML430 120K Miles

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99 ML430