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Power Steering Problem

45K views 38 replies 15 participants last post by  Sladew2 
#1 ·
Greetings to all Members!

This is my first post, I have bought a 2004 325i auto in the last couple of days. Black on black with 105000 kms.
Nice car, has a couple of light scratches but overall fairly well maintained. Bought it at auction so had no chance to test it beforehand. Drove it home OK, but yesterday I noticed that the power steering was not working with the car idling and my foot on the brake, but it would kick in once I drove off and the revs rose. This morning from a cold start the power steering worked fine, but after a while once the car got hot I noticed the power steering doing the same thing and not assisting while car is idling.

Anyone else had this problem or have an idea of what it could be. Fluid level seems to be fine.
 
#3 ·
You need to check the oil levels whilst hot...you might fine the levels are low when hot. Just an idea for you!
 
#5 ·
Just a thought.... you might like to check for any leaks along the PS reservoir and connecting hoses. If there are leaks, you may not be able to see them looking from above, would be best to check from underneath after removing the shield below the engine. Colour and texture of the ATF is markedly different to engine oil so you should be able to indentify it easily.
 
#6 ·
Check / change your ps fluid ..... also check your reservior for cracks.....
Mine had a similar issue to yours but after flushing the system and new oil it went away after a few 100 kays..
 
#9 ·
OK so I emptied my reservoir using a 10mL syringe (couldn't find a baster), and refilled for a total of 5 times. Car was driven and wheel turned lock to lock while stationary a number of times in between flushes to ensure proper mixing of old and new fluid. Fluid was pretty black and milky to start with, then after 3 flushes it was reddy black, and then pretty clean looking after 5 flushes. Went through about 1.5L of Dexron 3 ATF.

Car still has the same problem. Secretly hoping that after some more driving the problem will sort itself out!
 
#10 ·
Did you ever find a solution to this. My car was doing the same thing. I changed the pump and now the problem has inverted :banghead: . Now the car wont have power steering in the morning on the first start. I rev it once.. and bang.. it goes normal..:hmm:.. I mean WTH.. is there something that freezes up during night.. its not even that cold its 30K here. I dont think its the temp though.. I have already changed the pump, the reservoir, two reservoir hoses.. anyone have any idea?
 
#11 ·
My problem was the plastic pump impeller had sheared off. I got a new aftermarket pump with a steel impeller and new hoses etc. Car has been good since.

Sorry but I am stumped as to the cause behind your issue. Your problem sounds bizarre - might need a specialist to have a look.
 
#12 · (Edited)
Thanks for the response.. its getting bizarre.. After prolonged debugging I have realized that if the car sits for about 6-7 hours the steering goes stiff. I put the leg on the pedal and rev its once and its gets perfect. I have wrapped some paper towels on the hoses which I suspect may have a slow leak but it has been 4 days now and the paper towels are fresh as new...I guess I will have to give in and loose a lot of change :(.. Will update you guys when I find something...Thanks
 
#13 ·
I have brand new hoses and completely fresh fluid in mine. The power steering is much heavier than it should be at slow speeds and a little hesitant until the engine revs climb. I suspect the sheared pump. Every now and then it drives perfectly for a short while, which is odd.
 
#14 · (Edited)
Raising an old thread here rather than start over. My car has had a brain snap for some reason or other.

Recent history:

1. Yesterday, while driving along the motorway, the DSC light and the amber park brake light came on with a beep. According to the book this means DSC failure. I've had this before and the codes showed there was a problem with one of the brake pressure sensors. Jiggling of the big electrical plug at the DSC unit and the wires to the pressure sensors fixed it the last time - at least 12 months ago. So this morning, I gave the plugs and leads a good jiggle about and took the car for a 16 km test drive. No repeat of the warning lights - excellent.

2. I exit the motorway from this test drive in a rather spirited fashion and bugga me :yikes: the power steering goes rigid i.e. no assist as I enter the exit and start turning.
So I struggle home with my now BMW truck. I've had a search on the forum and will do some more but I need some more ideas.

So far I have checked the following:

1. Taken off the splash shield and had a good look around under the engine bay - no leaks of anything anywhere and nothing on the inside of the splash shield.
2. Thorough check of the PS pump area and no leaks or busted pipes/hoses or anything. It is a LUK LF20 pump.
3. Took off the serpentine belt and P.S. pump shaft is not broken. Belt is not slipping.
4. Checked the fluid level -all OK and clean red. Cannot ascertain whether fluid is returning to the reservoir when the PS pump is running though.
5. No whines or odd noises coming from the PS pump.
6. Jacked up front end and worked wheels from left to right and back a few times by hand - no problems detected

I can't see how the DSC failure warning and this PS problem could be related but it is a BMW...

Has anyone out there got any ideas or experience with this sort of issue?
 
#15 · (Edited)
I could suggest the seals in the rack are bad allowing pressure loss in system. Just like in vanos, seals go bad fluid passes right through. My 2¥. I think the only way to verify rack seals bad would be to loosen boots on rack. If anything there besides grease, ie ATF fluid, there's your problem. Worth the investigation. Cheap to replace boots, if that's not the problem.
 
#17 · (Edited)
Btw, I had a loose connection at the bottom of my pump which was slowly leaking fluid, but it was also making the steering much harder to turn.


EDIT: John! Please change your rack :p If it fixes it I'll do that too hahaha. And Justin from BMWreckers has a rack pretty cheap if you need one, definitely not the $1100 that the OEM supplier wants for a rebuilt rack :S
 
#18 ·
...And Justin from BMWreckers has a rack pretty cheap if you need one, definitely not the $1100 that the OEM supplier wants for a rebuilt rack :S
:bawling: $1100 :yikes: jeeeebus! Thanks for the heads up on the wreckers Tom.

I'm sort of hoping it's some sort of internal pump failure like a stuck relief valve or something but I'm probably clutching at straws. If only I could test the pump output pressure....

I could do the pump replacement myself but the rack looks a bit too hard for an "under the carport" job.

I'll get onto RX Automotive in the morning and see what they think.

....and we didn't win Lotto last night so we can't afford that M135i either.
 
#21 ·
After searching all over the interweb yesterday and last night, I cannot find a single case of total hydraulic failure of the power steering rack. Plenty of pumps though. A lot of enquiries today and no one has had any experience of a rack hydraulic failure but have seen pumps fail.

So, I've ordered a new pump and reservoir from Clickable and will start pulling the suspect bits off tomorrow.
 
#25 ·
late last year my car became a truck as well. bought a new power steering pump off lucas, took it to the mechanic and all was well. cant tell you what exactly was wrong with the pump as i dont know................................
 
#26 ·
Pump is off. Mix up with parts. Spent the afternoon disassembling pump just for the hellofit.

Shaft is OK but it looks like the impeller blades were stuck fully retracted - probably the cause of no pressure.

Took the impeller out and removed each blade - some needed more encouragement than others. Once out and given a wipe they slipped in and out of their grooves OK.
 

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#27 · (Edited)
Well, I put this pump back on today to see how it would go. It worked! for about 5 minutes on a test drive and then the system started having whines and rumbles when any power assist was required. It was worth a try and at least, for me, shows why/how the pumps fail.

So it looks like the impeller/pressure chamber design is the cause of the failures. It seems to me that microscopic particle build up on the impeller causes the vanes:

1. to jam closed - no sheared shaft but no pressure; or
2. to jam open - rotor jams and shaft shears as it is designed to do at the weak point where the rotor fits.

I guess this reinforces the notion that it's worth flushing the PS system every 25,000 km or so to reduce/prevent particulate build up.

I'll get a new pump tomorrow and hopefully fix the PS on my car for another 150,000 km.
 
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