84 533i power steering noise

Ray Bryan · Post by **Ray Bryan** » Oct 27, 2005 2:02 PM

I am trying to eliminate a loud squeal and grinding noise from my power steering. The noise is coming from the high pressure line between the pump and the brake regulator. You can feel and hear a strong singing vibration in the line while it's operating and both the pump and the regulator are making some noise. Any ideas on how I can troubleshoot? It is a classical kind of bad-pump squeal and grind, but the pump is only a few months old. I think it might be the regulator but I don't want to shotgun a replacement for the regulator... big bucks even for a used one.

The problems started when my power steering hoses developed some minor leaks and the system eventually got low on fluid and noisy. I've topped up the system, fixed the leaks and also replaced the pump with a new (used but known good) pump. The noise developed gradually over a few months period.

I've also recently replaced the brake master cylinder with a rebuilt, and also the hydraulic booster. The brake accumulator and the regulator are both possibly original on a car with 270K miles (I've owned it since 200K).

I've done the recommended procedure to bleed the system... full lock back and forth on the steering wheel... and the noise persists. I've also recently discovered that the power steering reservoir does not have a filter in it!... just the screen. I didn't know it even needed one until I was working on this problem... so it's been running for a few years without a filter.

Any ideas? I'd prefer to isolate the problem before I throw in any more parts.

Post by **Shawn D.** » Oct 28, 2005 7:50 AM

I'd start by installing a filter. Are you sure it doesn't have one? The screen is at top and you have to remove it and then have the fluid level below about 1/3 before the filter comes into view.

Ray Bryan · Post by **Ray Bryan** » Oct 28, 2005 2:23 PM

Yep, it does not have a filter. I had the entire reservoir off so that I could put the new brake master cylinder and hydraulic booster in.

I've got a filter on order which is due in today, so it'll be in there tonight.

Last night I pulled out the pressure regulator and accumulator to see if there was anything obvious. I was hoping that I might be able to run some solvent through the regulator to flush it out. I didn't really see much and I tried to flush it out but who knows if it helped.

Thanks for the suggestion.

bmws forever · Post by **bmws forever** » Oct 29, 2005 9:22 AM

Is the ps fluid foamy? If so, that's a clue that there is air getting into the system. Make sure all four bolts are installed tight into the ps pump. Note that the mounting brackets use some of the same bolts that keep the pump halfs together.

Ray Bryan · Post by **Ray Bryan** » Oct 30, 2005 2:37 AM

No, the fluid is not foamy. I had a few minor bubbles during start up but those subsided.

Thanks for the suggestion about the pump bolts and mounting bolts. I did check them and they are tight.

I'm going to try swapping the pump. I'm not 100% certain it's bad but it's old and a re-man is not expensive.

Ray Bryan · Post by **Ray Bryan** » Nov 07, 2005 3:10 PM

OK, the new pump is in and the noise persists. I have bled the system a number of times according to the standard procedure. There are no bubbles in the ps reservoir. The steering and brakes work fine but the noise is LOUD! The high presssure line is vibrating along with the noise... it seems to come from the line and the pressure regulator.

I wonder about the pressure regulator. How do I test it?

bmws forever · Post by **bmws forever** » Nov 07, 2005 4:19 PM

wow, really don't know. But, i think i would put a pressure gauge on the high side and compare with the value i read in Bentley one time. SOmething around 1000psi, as i recall. 0 to 3k psi gauges are easily obtained, the trick may be in finding the adapter that MAY screw in place of one of the sensor switches.

Ray Bryan · Post by **Ray Bryan** » Nov 14, 2005 1:34 PM

Thanks, I will look for a gauge, but I agree it may be hard to find with a matching fitting for the regulator. I've had at least one BMW mechanic tell me that the pressure regulators never die, but all signs point in that direction. I may shotgun this and just get a used one, but we're still talking almost $200. Oh, well.

I put everything back together and test drove the car with the noise, and realized that there is no power assist. Just turning the wheel in the garage with the car on jackstands, it sure felt like there was some power assist still there. But on the road... clearly nothing.

So there is either no pressure getting to the steering rack or the rack itself is fubar... maybe a clog or it's just gone south. ALL of the noise is coming from the high pressure line between the pump and regulator, so I suspect the regulator. I really need to know what's happening bet ween the regulator and the steering rack itself. Maybe I can pull the return line from the steering rack and see if there is some fluid coming through... at least that would tell me that it's not completely clogged.

rothj6 · Post by **rothj6** » Jun 19, 2010 5:33 AM

Make sure fluid is getting to the pump...

abdoosh00 · Post by **abdoosh00** » Jun 19, 2010 7:35 AM

I've read on this forum before a similar issue, and by replacing the high pressure supply and the return lines which were collapsing under high pressure, it cured the problem. I would check and replace all the lines before paying for $$$ things. At least if that dsnt solve ur problem u will have fresh new hosing for the system.

knowITall · Post by **knowITall** » Jun 20, 2010 2:10 AM

Not to get all into this but a few things.
1. Only ATF in the system no "power steering" fluid of any kind. Non pressure hoses must be made for oil. A small round coin like valve can drop out of the accumulater valving system when your not looking when replacing the bomb. There is a filter in the res. at the bottom than can in bad cases clog up. All in all this system with only ATF in it and a filter change here and there and a bomb when needed is pretty tough system.

Lubehead · Post by **Lubehead** » Jun 04, 2011 4:56 PM

knnowITall wrote: A small round coin like valve can drop out of the accumulater valving system when your not looking when replacing the bomb. .

On my '87 535is, this device, which appears to be a check valve did fall out while I was changing the accumulator. The O ring was damaged. Looking carefully at it I replaced it (with a new O ring) with the triangular plate facing upwards and the piston that retracts against spring pressure pointing down. There was a 50/50 chance of getting it right. Now all back together, I cannot get the power steering pump to stop groaning and no amount of bleeding appears to effect it. Does anyone here know the proper orientation of this check valve? I'm thinking if it's installed incorrectly this could be the cause of my issue.
Appreciate your assistance.

TSMacNeil · Post by **TSMacNeil** » Jun 04, 2011 5:26 PM

Nope. But groaning can be as simple as adding ATF, or tightening the pump case bolts themselves. If they get loose, el pumpo does el groano mucho.

Lubehead · Post by **Lubehead** » Jun 04, 2011 6:57 PM

Thank you, fluid is topped off, bolts are tight- pump didn't groan before accumulator replacement. Do you know for a fact that the check valve is installed correctly?

TSMacNeil · Post by **TSMacNeil** » Jun 04, 2011 8:44 PM

Lubehead wrote:Thank you, fluid is topped off, bolts are tight- pump didn't groan before accumulator replacement. Do you know for a fact that the check valve is installed correctly?

I'm sorry, I don't. I haven't had to deal with the accumulator yet.

Lubehead · Post by **Lubehead** » Jun 05, 2011 6:05 PM

I pulled the regulator assembly this time as the check valve would not come out. Clamping it in the vise, I was able to see through the hose port (hose running from master cylinder to regulator) and could clearly see the O ring of the check valve. Since the O ring didn't seal against a surface at that point, it was obvious that it was in upside down. I dug it out and inserted it with the triangular plate oriented downward and the small piston pointed up.

Reassembled and still could not get the steering pump to quiet down. I am moving forward on the assumtion that having the check valve improperly installed may have starved the pump and damaged it, as the PS pump did not make any noise prior to replacing the accumulator. I'll do some more searching before I replace/rebuild the pump as I definitely would like to confirm that the pump is indeed bad.

afireinside1988 · Post by **afireinside1988** » Sep 10, 2012 2:30 PM

Having the same issue with my 87 535i. Just replaced the accumulator last weekend and dropped that little coin size valve in the process. Having no idea the orientation of this valve I just went with my "best guess", if you will. Now I have a constant p.s whine that i can't seem to get rid of. Brakes and steering work great. Brakes are actually better than ever. I have bled the system per bentley 3 times and I'm running dex III trans in the res. There is no foam or air bubbles, fluid level is 10mm from rim. Did you ever find anything about your car's issue Lubehead?

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84 533i power steering noise