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Discussion Starter · #1 ·
Changed almost the entire power steering assembly about 2 months ago and up until yesterday everything seemed to be OK, no noises, no PS pump whining (well, PS was still rather stiff and was squeaking somewhere around the steering wheel but I think that had to do with some worn bushings on the power steering rack, which for the price it takes to replace it ... I'd rather buy another BMW). But I divert ...

Yesterday evening I started my car, and the moment I attempted to turn my wheels, I could hear a loud whining from the power steering pump (you just can't ignore that noise :cry:). So I popped off the hood and witnessed pink ATF foam coming out of the PS reservoir :eek:. The engine was still running at the time. Took off the cap from the reservoir and ATF was "bubbling" inside ...

This morning I opened the reservoir again and realised is was way overfilled :confused: ... hmmm, maybe **I** did that two months although I don't remember going overboard with ATF. Anyhow, the ATF liquid inside was back to its ruby colour, relatively clear and no traces of foam or bubbles. So took off the excess ATF, started the car and shortly after, the ATF inside the reservoir began to "boil" again. Pretty significant air bubbles were belching continuously.

So the return pipe is throwing back a lot of air. Where could this air be coming from ? Could the intake manifold be obstructed ? All the hoses, clamps and crush washers are new. Could it get air from the power steering rack "connection "?

Any opinion/advice is most welcome ! Thank you.
 

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Discussion Starter · #2 ·
Well, well ... looks like both clamps on the hoses that connect to the reservoir have "set" since I did the PS job. Was able to tight them quite a bit and ... presto ! Problem solved. :drive:

I guess it's no small feat for the PS pump to suck the thick ATF fluid through the reservoir filter so the connections must be very tight otherwise it will suck up air instead :D
 

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D'oh, You Kids!
1984 633CSi, 1985 635CSi, 1985 325e, 1987 325is, 1993 325is, 1995 318is, 1995 M3, 2003 F150
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Thanks for posting back...I missed this earlier. Well done. :clap: :thumbup:
 

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Discussion Starter · #4 ·
Well, I was celebrating too early ... :( Yesterday morning it happened again. Checked all the bolts torques and they were OK. The clamps were tighten to the max. So I was at lost ... :dunno:

Then I noticed some ATF drops on the ATF pump itself. The front of the car was on ramps so I was able to trace the apparent source of the leak to the front of the pump (the banjo bolts were bone dry).

Miraculously, just as sudden as it started, the pump whining faded away after a while, without me doing anything to fix it :confused:.

So all-an-all now I believe the pump is on its way out (pretty much the only cause I can think of). Since the ATF is pumped under high pressure into the steering rack, the pump shouldn't be able to suck air from there (unless the pump is broken, of course). If any air enters into the system as I turn the wheel, it can only come from the pump itself or along the intake hose.

I will replace the pump this weekend with an old one I have handy. The other option would be to buy a rebuilt unit from Atlantic Enterprise (sold by wwww.pelicanparts.com). Anyone had any experience with the rebuilt pump ?
 
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