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Discussion Starter · #1 ·
That about sums it up. My 540i will not turn the wheels when it's running, I can tell the pump is trying as it chirps the belt when it weights up. What's really weird is that when I have the key in the on position but the car isn't running, I can with effort turn it, as one would expect. I don't dare put too much effort into turning it when it's running for fear of blowing the pump or lines. Revving the motor makes no difference at all.

I just don't understand why I can't turn it when it's running but I can when it's not. I'd like to get the front of the car off the ground, but I always need one wheel on the ground for safety on account of the ground not being level in the space I have available to work(side of a fairly aggressively cambered road.) I'm trying the grease the u joint trick now, but given I can turn it with the engine off, I'm not optimistic. I did hear tell of a sensor in the rack that can fail, but further details on it or how to diagnose it I can't find. I bought the car with failed chain guides, so I can't speak at all to how it was before and having been an auction, I didn't meet the previous owner. Has anyone seen this weird combination of symptoms before?
 

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Certifiable BMW Whackjob!
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You know how old the fluid is? Perhaps it is due for a flush.
 

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There is no rack on a 540. What do you mean "it chirps the belt when it weights up."

If you remove the belt, can you turn the power steering pump by hand? It should turn very easily.
 

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You do not have a "rack" (Rack & Pinion Steering), you have a Recirculating Ball Steering System.
 

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Checking the U-joints at the bottom of the steering column.
They are similar to driveshaft U-joints...
 

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Discussion Starter · #6 ·
There is no rack on a 540. What do you mean "it chirps the belt when it weights up."
When I try to turn the wheel, I quickly encounter very sudden and very strong resistance, and if I push against it, the belt chirps.
 

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2001 BMW E39 540i Automatic Sedan, 198 K milesmiles
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Naive question : When did the problem start ?
Did you do any work on the suspension underneath the car, or near the power steering pump or belts ?
Inspect the power steering pump, reservoir and hoses for leaks. Did you mix power steering fluids
 

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Discussion Starter · #9 ·
After soaking the u-joint in the steering shaft in WD-40 for a day and then White Lithium grease for another day, the problem is exactly the same. I do hear a pulley noise when the engine is running, like a bad bearing, but it sounds mild, not the screeching of a totally gone bearing, more of a light scrape. The battery light is also on, so I don't know if the alternator is charging or not.

Naive question : When did the problem start ?
Did you do any work on the suspension underneath the car, or near the power steering pump or belts ?
Inspect the power steering pump, reservoir and hoses for leaks. Did you mix power steering fluids
I bought the car from a Copart Auction with chain guide rattle so bad, I didn't dare start it again until it was fixed for fear of losing time and blowing the motor. So, the first time I tried to turn the steering wheel with it running, it had this issue. I'll inspect the power steering system and report back.
 
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