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R50 power steering pump

9K views 2 replies 2 participants last post by  Rally370 
#1 ·
From day one I've heard this pump/fan noise from under the engine and really never bothered about it as I was new to the car. Now the Mini is finished I thought I'd investigate the noise.

If I turn on the ignition but not starting the engine I can hear this noise. I found out it is the power steering pump working. I can tell because the steering is easy to turn. The pump seems to increase and decrease in speed without moving the steering wheel. The pump is basically running most of the time and sometimes not running resulting in no power steering.

So what controls the pump to make it work?
 
#2 ·
I think the other Mini2 thread has probably answered your question, I have more detailed info on the contol system in a pdf guide which I can dig out but this MCR thread below has lots of ps pump info and links gathered together:
Power Steering Pump replacement - Forums

"The EHPS system on mini's (electro hydraulic power steeering) is a two stage steering system/process.
When NO steering wheel movement is carried out the pump runs at 80% its output.
When any movement of the steering wheel is carried out the hydraulic pressure in the system increases thus the pump runs to its full 100% output."
eg:-
80% output spin speed is 3500 rpm
100% output spin speed is 4500 rpm.
 
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