Power Steering Problem

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.

Originally Posted by Brissyjohn

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.

Yup. I have never heard anything like it before, hence why I also still have my problem :


Let me know how you go! Would also love to come and help if you're not too far north? I suspect I'll be delving into the same places sometime soon myself.

I'm in Jindalee - 0401 752795. Will be starting the removal at about 7:00 am. Hope to have it off by 9:00 am. Parts probably won't be here until tomorrow.

Sounds good, you're not too far at all. That'd be great!

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................................

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.

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.

Nice work! Interesting to see how it all works....

Thanks for posting those pics John! I've never torn into a PS pump before, and it was interesting to see the internals and hear your thoughts on the failure.

Update: So I pulled the pump off again today ready for the new one. Couldn't help myself and pulled it apart again to see what's going on. You need a #40 Torx bit.

All the impeller blades were free to move except one. I then noticed (under a magnifying glass) that the blades have a rounded edge and a flat edge. The slots are rounded at the axis end and I'd put a couple of blades in the wrong way i.e. rounded edge out. So I cleaned it all up again and reinserted the blades rounded edge in. I went over to Queensland Hydraulic Services who very kindly gave me (no charge) a 64mm ID, 2mm "O" ring for the case. Reassembled the pump.

So, I couldn't help but keep thinking that the problem that arose on the test drive yesterday was an air lock and that the pump was probably working - it did for the first 5 minutes. So I pulled out the reservoir and emptied it out and gave it a wipe.

So far all that this exercise has cost me is my free time, a drive in the MX-5 (hardly a task) over to Salisbury to get the "O" ring and 500 ml of Dex 111. So what's another 500 ml of Dex 111 out of the 4 litres I bought? So I put the pump and reservoir back on, buttoned everything up and filled the reservoir.

Turned the engine over and switched off after a couple of seconds to prime the pump. Re-checked fluid level - small top up needed. Had a beer to think - it was 4:00pm after all. Ran the engine a bit longer, still no weird noises. Checked fluid, had another beer. Drove the car up and down the (double width) driveway and moved it across from side to side without using huge steering angles. No noises, no fluttering through the steering wheel...and we have power steering again! Wooohooo!

Had too many beers by then so will leave the hidden air bubbles to rise overnight and take it on a careful test run tomorrow. Fingers crossed.

Footnote: I think it's pretty poor that a premium Euro car such as the BMW has this sort of failure though. I've seen plenty of cars (Holdens, Falcons, Japanese) that have been driven into the ground - and then another 100,000 km - and the power steering still worked fine and had never been touched. This failure shouldn't happen at 150,000 km in a modern car.

Awesome feedback.... looking forward to test drive results.



Sent from my V9 using Bimmer App

Well, a few test drives around the suburb this morning through all the streets and no problems. Covered 6 km of twisty bits now and it works like a bought one - leak checked all okay. The missus has taken the Bimmer to the shops now so there's confidence for you.

The reservoir started off slightly over filled but, after the first test run of 1.6 km, it was down to just touching the dip stick - close to taking in air again. So I reckon what happened on the failed attempt on 16 Jan was that the reservoir got very low and the system took in a gutfull of air that I couldn't remove.

I guess I got it out with yesterday's "extreme" flush i.e removal of pump and reservoir, fix pump, refit everything, refill, go slowly on the bleeding process (drink a few beers) and keep an eagle eye on the reservoir fluid level.

I won't be happy until we've covered a few hundred km. I'll keep the new pump just in case but it may be for sale at a bargain price in a few months.

Final tips:

1. Get the front wheels off the ground if you can prior to running the engine and initially exercise the steering wheel just a half turn each way s-l-o-w-l-y. I couldn't do that as the car was out in the carport on a 1:6 slope with the front wheels on 100 mm of wood so I could get under the front of the car- see pic. I recommend 150 mm elevation to get just a bit easier access. I couldn't put the car in the single garage (the only piece of flat ground for miles) because that's being repaired and painted after hail storms in December.

2. Check the fluid level in the reservoir frequently during the bleed process and just take it a little bit at a time. Be patient - something I'm not good at.

3. If you want to flush the system, don't be a pussy and mess around with turkey basters etc. Undo the two connections at the pump and drain the oil. Then plug the pump delivery line (rubber hose), remove the airbox (easy to do but plenty of DIYs out there), and remove the reservoir. Put a plastic sheet and lots of rags over the alternator when you do this - you don't want to replace the alternator at $$$ because it got filled with ATF do you? Wipe out the reservoir with lint free clean rag, put everything back on and do the bleeding process.

4. The BMW "only use once" hose clamps do not have to be broken off or cut off. You can just unclip them by using a thin blade screwdriver under the claw of the clip - see pic. Replace them with jubilee clamps and do not over tighten - you'll need three clamps (one for pump and two for the reservoir) if the car is original.

That's a fantastic result... well done and keep us posted on any development.

Our "Premium Euro Cars" require considerably more maintenance than the other cars you mentioned. Most of the components also seem more likely to fail.

European cars deserve every bit of the reputation they get. The day someone else makes a more reliable car that is in every way as good as my 330i, I will buy it. Till then, I'll keep fixing the Piece of SH*T

Originally Posted by esamc2

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

Did you ever figure this out? After I replaced my power steering pump I've had the same problem every time it is cold outside. Rev engine fixes and then I'm off.