535i power steering problem defies experts

[jstcl]

Hello, I have recently bought a beautiful 1985 535i, with full knowledge the power steering pump which was leaking needed replacing. Upon replacing it, the new pump started emitting a VERY loud whining noise, which was loudest at low rpms, and when cold. When warm, and upwards of 2500 rpms, the noise almost completely abated. Also when cold practically no assist to the steering. When warm, assist returned.

Took it to a shop which has specialized in BMW for 20 years here in Boulder, they took it step by step. First get another pump installed. No change. Then then next link to replace was the fluid apportioning valve (directs half pressure to steering box, half to brakes), a $650 part. No change. Lines were rerouted to see if the blockage was in the steering box. The problem is not in the steering box.

After 3.5 hours of labor and no resolution of the problem, he had to admit he was stumped. Anybody out there ever had this problem, and if so, what solution???
thanks,
hoping to catch this ghost in the machine,
James

 

[PMcD]

Well my sister had an A4 Audi that did practically the same thing, come to find out it needed a special mineral oil type P/S fluid, when we got some it worked just fine and the noise stopped.

I hope that can help you.

 

[E30m42cab]

They're using ATF right? not power steering fluid? My girlfriends E30 was squeeling like a pig, because someone put stop-leak and power steering fluid in it, and it felt like there was no PS, especially when it was cold... I drained it all, put ATF in it, and she runs like a champ now. Oh, and isn't there a filter in your fluid reservoir? Changed it?

 

[Big Daddy]

Besides using ATF has the filter been replaced? For an 85 535i: Power Steering Fluid, Dexron-II ATF Or Equivalent

 

[ZombieHunter]

I don't think he's gonna answer. The original post is almost 2 years old...