Power Steering Trouble Shoot

Specific conversations and info for the BMW E28 M5 and M535i.
underwatervans
Posts: 232
Joined: Apr 10, 2008 12:08 AM
Location: Charleston, SC or Ocean City, MD

Power Steering Trouble Shoot

Post by underwatervans »

So, after having my car sit for about a month the power steering screams every time I turn the wheel. It still works its just very loud. I changed the belt and pumped the brakes 20+ times and turned it lock to lock but still the scream. Anyone know whats going on? Anything would be great!
Blue Shadow
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Location: SE PA

Post by Blue Shadow »

change the fluid and filter.
M5BB
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Location: Peachtree Corners, Georgia

Post by M5BB »

Yes, try what Blue Shadow says.
Be sure and drive the car and turn the wheel to R&L many times to work the air out of the fluid.
Also check to make sure a hose has not collapsed.

Here is a conversation i had just the other day with a guy.

Hi Gary,

You've got it bad! From your description I would have guessed it was the power flow regulator, but I guess not. I don't have any suggestions for you right now, but I do have some documentation that you might be interested in. I have a cutaway view of the flow regulator, with an explanation of the fluid path. I'll scan it in and send it. I can't promise that I'll get to it on Sunday, but I'll get it to you shortly. If you don't see it in the next couple of days, feel free to remind me. This power steering system has been giving me problems ever since I got the car in 1992.

Larry

> > Subject: RE: Power Steering
> Date: Sat, 24 Jan 2009 22:36:09 -0500
>
> Hey Larry, nice to hear from you.
>
> Man, all I can say is what a pain! I'm still having problems.
> I had multiple pump problems. Currently have a rebuilt pump for the M5.
> Replaced the filter in the reservoir as the first item. Then two pumps as
> one was a failure and on the second right now but suspicious it is leaking.
> Then removed all the hoses that go to the pump to make sure there was no
> blockage. Still problems with jerky steering but no pump noise.
> Then replaced the power flow regulator for $430 or so because it seemed to
> be an overpressure situation. Seemed like that had done it but was getting
> some fluid on the ground and then the other day I drove it for about an hour
> and the pump started making noise even though the fluid level was ok. Shut
> it off for a few hours at a concert and then drove home with no noise.
> Put on a friends rack today and could see where fluid was coming off the
> steering box and maybe that lower fitting. Put two new round copper seals on
> that fitting but could also see drops on the bottom of the power booster
> part of the master cylinder.
> My friend had some dye so we put some in the fluid and will look in a few
> days with the UV light and see if we can tell if there are any other leaks.
>
> The problem with the power flow regulator is there is no easy way to test
> although the Bentley has some pressure numbers for it but never explains how
> the regulator works and what the pressure valves do?
> I hate just throwing parts at problems but it seems to be the way this is
> working.
> Do you know any more or know anyone that has any better trouble shooting
> info?
> Later,
> Gary
>
>
> > Sent: Saturday, January 24, 2009 5:54 PM
> To: Gary Beck
> Subject: Power Steering
>
> Hi Gary,
>
> I was looking through the archives and saw that you had a pressure
> problem with your power steering system a while ago. I didn't find
> any followup posts about it so I was wondering if you ever solved it?
> I think I might be experiencing something similar and I have a choice
> of replacing the steering gearbox or the "power flow regulator"
> located above the accumulator ("bomb"). Both are very expensive.
> Have you had any luck?
>
> Thanks,
> Larry
underwatervans
Posts: 232
Joined: Apr 10, 2008 12:08 AM
Location: Charleston, SC or Ocean City, MD

Post by underwatervans »

Yeah, I just bought fluid and a filter from Steve. Hopefully this fixes it, but he told me that the PS pump is basically the same as the 535 so if worst come to worst I'm going to try that. Everything works fine its just a wicked noise coming from what seems to be the pump when I turn the wheel from lock to lock. I put it up in the air and turned the wheel and there wasn't a noise at all, but then I remembered there was no pressure on the wheels. So obviously this is a pressure problem. Mmm and by the way it looks no one has seen how to fix this directly. Thanks for the help I'll get back to you when I change the fluid and filter.
M5BB
Posts: 1555
Joined: Jun 13, 2007 10:13 AM
Location: Peachtree Corners, Georgia

Post by M5BB »

Forgot to mention there is a rebuild kit for the PS pump.
About $35 from Steve.
I tried it and it didn't work.
If you get one be careful taking the pump apart as there are little vanes in there that will go all over the place.
underwatervans
Posts: 232
Joined: Apr 10, 2008 12:08 AM
Location: Charleston, SC or Ocean City, MD

Post by underwatervans »

Yeah I see a similar situation you were in, well hopefully it doesn't get that bad and this cures it. One can hope anyway.
bionicjoggingsuit
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Joined: Jan 18, 2009 6:51 PM
Location: Bishop, GA

Post by bionicjoggingsuit »

Is the Power steering fluid frothy? The noise: you described it as a scream. Is it high pitched or more of a moderate frequency rumble, yet so loud and "broke" sounding that a 20 acre parking lot full of people stare at you when it happens?

I went through all of the could be's on mine. Turns out it was pump cavitation and the point of entry for the offending air was the body of the pump itself. The PS Pump is 2 halves held together with 4 bolts. one bolt was only finger tight and another was a tad loose. Tightened up the bolts and the worlds most irritating noise has vanished!!
M5BB
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Location: Peachtree Corners, Georgia

Post by M5BB »

Bionic,
Good info. I will check the bolts as you mentioned.
I have been having problems for a few months.

No, fluid is clear just like it comes out of the bottle.
It is making a lower pitched growling noise at idle but not when the revs are up.
You can drive along and go to turn a corner let off the gas or push in the clutch and it will go to idle and it will be like you don't have any PS and then all of a sudden it will catch
and work normally. A little scary.
I just wonder now if the steering box is doing something strange. I'm sure sick of fooling with it. It's also connected to the power booster which is part of the master cyl. Big ticket item to replace.
Larry from above sent me some details about the system but without a bunch of gauges and fittings i have no way to test.
I also emailed a guy who has an indi shop and owns an M5 but i have never heard back from him.
So on we go.................
underwatervans
Posts: 232
Joined: Apr 10, 2008 12:08 AM
Location: Charleston, SC or Ocean City, MD

Post by underwatervans »

Wow, that describes exactly what is happening. Ill get in there and tighten them up I haven't had any loss in Power steering but that scream makes me cringe and its just terrible I'll try that and see if that is it. Thank you I'll get back to you afterward. I'm going to change the fluid next week the parts from steve havent come in yt.
bionicjoggingsuit
Posts: 94
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Location: Bishop, GA

Pump cavitation

Post by bionicjoggingsuit »

underwatervans wrote:Wow, that describes exactly what is happening. Ill get in there and tighten them up I haven't had any loss in Power steering but that scream makes me cringe and its just terrible I'll try that and see if that is it. Thank you I'll get back to you afterward. I'm going to change the fluid next week the parts from steve havent come in yt.

Yeah, I even wasted 3 litres of expensive Pentozen (misspelled probably) flushing out the red GM ATF that my mechanic was 100% sure was the culprit and cause of the noise. I replaced the filter which appeared perfectly fine. It might have needed it anyway. The main thing is the that even if your pump bolts are tight, don't give up. If your fluid is frothy in the least, then that means air is being introduced into the system on the vaccuum side of the operation. Check your low pressure lines for cracks or loose clamps. Its a sneaky thing. Mine was such a small leak that once the car got up to operating temperature, the noise would subside completely but man when the car was cold, the noise was so bad I started hiding under my dash out of embarrassment when I pulled out of my driveway in the mornings.
Shawn D.
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Re: Pump cavitation

Post by Shawn D. »

bionicjoggingsuit wrote:Yeah, I even wasted 3 litres of expensive Pentozen (misspelled probably)...
Yep -- it's Pentosin. Why would you go to that when the system is specified to use Dexron (the "red GM ATF")?
bionicjoggingsuit
Posts: 94
Joined: Jan 18, 2009 6:51 PM
Location: Bishop, GA

Re: Pump cavitation

Post by bionicjoggingsuit »

Shawn D. wrote:
bionicjoggingsuit wrote:Yeah, I even wasted 3 litres of expensive Pentozen (misspelled probably)...
Yep -- it's Pentosin. Why would you go to that when the system is specified to use Dexron (the "red GM ATF")?
The mechanic I use recommended it. Just following his suggestion.
VW+bimmer=bliss
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Post by VW+bimmer=bliss »

you should tell that mechanic he was wrong in his decision, pentosin is a bright green hydraulic fluid used in suspension components such as the SLS on m5's and mutiple other cars such as rolls royce, etc, etc...
John in VA
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Post by John in VA »

Deutsche Pentosin-Werke GmbH, commonly known as Pentosin, is a global independent manufacturer of brake fluid, antifreeze, power steering fluid, ATF, motor oil, etc.
VW+bimmer=bliss
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Post by VW+bimmer=bliss »

John in VA wrote:Deutsche Pentosin-Werke GmbH, commonly known as Pentosin, is a global independent manufacturer of brake fluid, antifreeze, power steering fluid, ATF, motor oil, etc.
i stand corrected ;)
underwatervans
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Joined: Apr 10, 2008 12:08 AM
Location: Charleston, SC or Ocean City, MD

Post by underwatervans »

So I tried tightening everything up to see if there was air getting in the system and still nothing. I haven't had a chance to change out the fluid or filter because Steven hasn't gotten my parts to me yet. I'll try tightening up and adjusting some things again tonight but the PS is working it just sounds like a broke down car at the moment
underwatervans
Posts: 232
Joined: Apr 10, 2008 12:08 AM
Location: Charleston, SC or Ocean City, MD

Post by underwatervans »

Well I thought I had tightened everything up but obviously not one of the bolts on the PS pump was loose when I went to check it one more time and presto noise gone. Thanks everyone for the help!
bionicjoggingsuit
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Location: Bishop, GA

Post by bionicjoggingsuit »

underwatervans wrote:Well I thought I had tightened everything up but obviously not one of the bolts on the PS pump was loose when I went to check it one more time and presto noise gone. Thanks everyone for the help!
Glad it worked. I was pulling my hair out on this issue. Amazing that it makes such a terrible noise from one slightly loose bolt.
M5BB
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Post by M5BB »

Well guys I'm still stumped. (see previous post above)
I have now changed the power booster too!
Still leaking from the PS pump even after I rebuilt that with a new seal.
Here's the senario....... When cold it is pretty good with no pump noise but when the fluid gets warm the pump starts making noise at idle, then when you drive the steering is fine at speed but when you go back to idle the power assist can cut in and out depending on the engine speed (pump speed).
So I have had two pumps, a new regulator and now the power booster and it still seems like there is a pressure problem as in over pressure (Leaking) or ???.
I have had the hoses off that come from the pump, pressure and return, I removed the canister and made sure they was not something in one of the pipes where all the hoses connect,
no dash lights from the switches on the regulator (from the ETM).
Don't know what to do next? :cry:
Any one have any ideas?
There are test procedures but only if you have a made up gauge set. These pumps can run up to 120 BAR (1740 PSI)
Not a gauge you can get at the hardware store?
JeepJockey
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Post by JeepJockey »

bionicjoggingsuit wrote:Is the Power steering fluid frothy? The noise: you described it as a scream. Is it high pitched or more of a moderate frequency rumble, yet so loud and "broke" sounding that a 20 acre parking lot full of people stare at you when it happens?

I went through all of the could be's on mine. Turns out it was pump cavitation and the point of entry for the offending air was the body of the pump itself. The PS Pump is 2 halves held together with 4 bolts. one bolt was only finger tight and another was a tad loose. Tightened up the bolts and the worlds most irritating noise has vanished!!
Thanks for this tip. I had "frothy" PS fluid from all the tiny air bubbles in it. Checked my bolts today and sure enough one of them was really loose. Tightened it up, pumped the brakes no more air bubbles. Tried to make it make noise and couldn't, so I am confident this fixed it.
M5BB
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Joined: Jun 13, 2007 10:13 AM
Location: Peachtree Corners, Georgia

power steering problem solved

Post by M5BB »

Finally i think i have fixed my power steering problem after six months. :banana:

Check the posts above in this thread so you can see what I have done.

After throwing money at the problem i have finally replaced the steering box with a used one from a know source. It was the only component that hadn't been replaced.
I guess my old steering box had some kind of blockage in it and was not allowing the fluid to get back to the reservoir causing the pump to wine and work harder then creating a leak at the front shaft seal on the pump.
I should also caution you to make absolutely sure the return hoses from the pump and steering box are not soft and causing partial collapse of the hose. the hoses need to be compatable with PS fluid and have wall thicknesses that will not allow the hose to collapse.
One other hose situation that can occur is the pressure side hoses (2) with the metal ends can have the liner inside the hose come loose and cause a blockage. Hard to detect.

BTW if you need a pressure hose and don't want to spend $200+ for the powers steering one you can find a company that makes hydraulic hoses for equipment and see if they can just replace the rubber part. They did the PS hose and steering box hose for $40 ea.
Hope this helps some others as trouble shooting info was very hard to come by.
eurodurance
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Post by eurodurance »

FWIW,

I had this exact problem a week or so ago when I took my car out of storage. It just belted out a horrific noise and I got stares of "WTF?" instead of "ZOMGE28". I did notice some fluid on my garage floor so I checked the resevoir and I was completely empty. First, I checked every power steering line/part in the car and nothing was doing.

I just filled it, scream went away, everything is back to normal. It doesn't leak anymore. After asking a local mechanic he said most car fluids will permeate through rubber hoses over time if it sits. Just like putting motor oil in a bucket, it seeps through no matter what you do. And I had a long point in the winter when I couldn't start it because I had from the head-up apart. Just FWIW.
jeffm2009
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Joined: Apr 17, 2009 11:21 PM

Re: power steering problem solved

Post by jeffm2009 »

M5BB wrote: BTW if you need a pressure hose and don't want to spend $200+ for the powers steering one you can find a company that makes hydraulic hoses for equipment and see if they can just replace the rubber part. They did the PS hose and steering box hose for $40 ea.
I know of a company called Gooding Rubber that have pretty reasonably priced quality hydraulic hoses. They may be able to help with any sort of hose work. Here's a link to their site: hydraulic hoses. Hope that helps.
mooseheadm5
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Re: power steering problem solved

Post by mooseheadm5 »

M5BB wrote:I guess my old steering box had some kind of blockage in it and was not allowing the fluid to get back to the reservoir causing the pump to wine and work harder then creating a leak at the front shaft seal on the pump.
I can has your old steering box to dissect?

<------- geek
M5BB
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Post by M5BB »

I found some good hose at a hydraulic supply company.
It is actually made for race cars. They have all kinds of high performance hose and fittings.
I called the stealer the other day and they don't even have hose you can buy by the foot. So that's out.
One hose I had tried has broken twice. It seems to get soft and is prone to tearing right near the clamp.
So be careful and buy the right type of hose for this application.

As far as the old M5 steering box............ I am probably going to rebuild it or at least open it up and see what might have caused the problem.
It's worth a $100 core charge so sorry I'm not giving it away.
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