Power steering whining

[BobRSnow]

Hi. I have an 87 535i. As of late, there's a whining that is coming from the PS. It's not making the noise when the steering wheel is being turned, but when I start the engine and for the next 10+ minutes as the engine warms up. Eventually the sounds is gone. It's bad in the morning, when the engine is obviously cold, and other times during the day when I get in the car. It's really bad during colder weather and it takes longer for the sound to go away.
My PS reservoir is full, too. Can anyone suggest what I should check next, like bleed a line out? I appreciate any suggestions you can make. Thanks.

[trevmmeister]

Filter in the bottom of PS resovoir. Probably gunked up. It goes away once the engine warms up because the fluids viscosity drops, making it somewhat easier to pass through the filter. Someone else chime in here; is that filter able to be cleaned?

Brainblast; is your PS belt tight? lol

[Kyle in NO]

Air in system. Tighten all of the bolts on the PS pump to start. Anywhere fluid is leaking will allow air in the system.

[ElGuappo]

Both of the above.

[Mike W.]

You don't even need fluid to leak to be sucking air. Tighten the bolts holding the pump together, tighten and consider replacing the suction hose from the reservoir to the pump. Mine was worse with a new filter until I tightened the bolts which weren't loose, but not quite tight. Wasn't even dripping.

[BobRSnow]

Problem solved for now. We disconnected the hose at the pump, and drained the fluid in the reservoir, pumping the brakes and all. Reconnect hose, fill fill fill. Pump brakes...Noise gone. Easier to handle. And that was yesterday. Today, my drive to work was quieter than I can ever remember. We'll see how this holds up.
Oh, and the belt was sufficiently tight. Thanks for the support guys.
Bob

[Buddyv]

New member / new E28 owner....

I am having the exact same issue with my 1983 533....... wondering why the solution included "pumping the brakes".....???

My other car does not have power steering, so pardon the ignorance here. I'm trying to get up to speed with my BMW. I have only had it for about a month.

Looking forward to replies..... and pics of parts I should tighten, if possible.

Thank you!

[ahab]

^^^
You have a hydro boost system in your car that uses the hydraulic steering circuit to provide power assist to the brakes. Typically what happens is the OE clamps and hoses loses their seal and the system goes low on fluid, causing the pump to whine or groan. This is more prevalent in cold weather. There is a cooler circuit up in the grill which is notorious for this. Unfortunately the OE clamps are crimp style and you're not able to tighten them (without getting creative), the best bet is to replace them with BMW clamps. Trust me, the Chinese hardware store clamps aren't going to cut it. Go to the dealer and drop $20 for quality hose clamps. You can also run your hand under the power booster and see if it comes out wet, indicating a leaking booster. As for the bolts to tighten, look at the power steering pump itself. There are 8 M8 bolts that hold the housing together, 4 per side. They can loosen over time. To drain the hydraulic lines or to check the level in the system you have to empty the accumulator by pumping the brakes. Your system uses ATF and not power steering fluid if you weren't aware. Do some searching here and you'll find out heaps more. And get a Bentley repair guide.

[Buddyv]

^^^
You have a hydro boost system in your car that uses the hydraulic steering circuit to provide power assist to the brakes. Typically what happens is the OE clamps and hoses loses their seal and the system goes low on fluid, causing the pump to whine or groan. This is more prevalent in cold weather. There is a cooler circuit up in the grill which is notorious for this. Unfortunately the OE clamps are crimp style and you're not able to tighten them (without getting creative), the best bet is to replace them with BMW clamps. Trust me, the Chinese hardware store clamps aren't going to cut it. Go to the dealer and drop $20 for quality hose clamps. You can also run your hand under the power booster and see if it comes out wet, indicating a leaking booster. As for the bolts to tighten, look at the power steering pump itself. There are 8 M8 bolts that hold the housing together, 4 per side. They can loosen over time. To drain the hydraulic lines or to check the level in the system you have to empty the accumulator by pumping the brakes. Your system uses ATF and not power steering fluid if you weren't aware. Do some searching here and you'll find out heaps more. And get a Bentley repair guide.

AHAB.... exactly the type of info I was looking for! Thank you.

Cheers!