Sticky steering --> fixed in Germany. What I learnt..

M

matthijsfh

Member
 Waalre, The Netherlands
Hai!

I just came back from a trip to Germany to have my sticky steering fixed.

Summary:
  • Two extremely friendly experts working on just Z4 cars sticky steering & torque sensor errors.
  • Very capable and knowing exactly what is going on.
  • I felt my bearing. It was clearly deteriorated. I felt the bearing of the other car being repaired. That one was toast. Must have been a nasty ride to get to the garage in the first place (guy had only 88k milage, car in mint condition)
  • Being able to feel my, his and their bearings convinced me the right part was replaced.

Insights:
  • The issue is the bearing very close to the steering wheel. It is hidden somewhere in the upper part of the column. The EPS / worm part of the column was not even touched.
  • This is an open bearing and made of various materials (different expansion on temperature changes) --> there's your problem.
  • BMW engineers tried to save some EUR and integrated the bearing with parts of the steering column --> the bearing is not a sperate "of-the-shelf" part at all.
  • NOTHING to do with the EPS motors gear / worm (more on that later).
These experts made their own replacement parts. Very cool engineering work with an integrated bearing. But this means you cannot fix this issue yourself, or your locale garage. They known and therefore charge serious money.

EPS disc adjustments
  • Why does everybody mess around with the excentre disc of the EPS???? ==> Because it does offer some initial (!) relief. The force of the worm-thing is partially loading the bad bearing. But the worm-gear is NOT the issue itself, nor is any friction of the worm. It's made out of some sort plastic and cannot generate high friction force due to the lubrication.
  • Okay, if lubrication is gone, fix that first. It might help.
  • If you adjust the excentre disc in the wrong direction (done that myself), you will get an effect similar to sticky steering. In fact you are loading the bad bearing even more, resulting in more stickyness.
  • Injecting grease (after drilling a hole) is NEVER going to solve the issue, as your are greasing the wrong bearing. The bad bearing is between the steering wheel and the EPS gear assembly.
So if you want to fix anything, take the upper part of the column apart and grease that 1st bearing.

I am confident the upgrade worked, but today is cold so I did not have any issues in the first place.
Don't expect miracles. According experts, the electric power steering on the Z4 is 2nd best compared to hydraulic.

My issue is solved, and this bearing would have gone bad on short notice anyway. This Z4 has 155k km milage. So bearing was about to go anyway. So glad I spent the time & money.

Grt Matthijs

Address:
Volker Rothschenk
+49 163.83 83 83 9
Birkenhofweg
40668 Meerbusch
 
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Interesting

The eps slip ring 100% HELPS the issue but I’ve never been convinced it RESOLVES the problem…

This is good to know and I’ll have a look
 
Thinking about this a little more. Engineer said that my steering column was removed before. So I am pretty sure the factory installed one had sticky issues and was replaced with another 2nd hand one. That explains the high mileage before the issues appeared.

Also the reason I thought this car would not have any issues. A lucky shot from the production line.

Have a 2nd column laying around (right hand drive, cannot use that column). Will take it apart and photograph the bearing we are talking about.

Grt Matthijs
 
I live in Breda and would be interested in making the trip to these guys. When you say serious money, how serious are we talking?.. Also, do you know any good garages in Nord Brabant for looking after e85 z4? Thks.
 
Yes, it is a lot of money but without the fix the car is worthless. So not many options.
But it would be nice if you just could send in the column for repair instead of driving there.

Greetings Matthijs
 
I can confirm Matthijs story and recommend Volker as THE expert regarding steering column issues here in Germany.
Lot's of engineering work gone into finding a proper solution.

I'm visiting him several times a year to discuss technical topics on our Z's. As he owns an E89 as well, even roof topics are discussed. :D

Z4 Lenkung - Nachhaltige Reparatur: Klebelenkung, Steuergerät, Momentsensor.

Z4Lenkung.de ist ein spezialisiertes überregionales Reparatur-Angebot für die Lenkungssysteme von BMW Roadster und Coupes mit Sitz in der Nähe von Düsseldorf.
z4lenkung.de z4lenkung.de

matthijsfh said:
Address:
Volker Rothschenk
+49 163.83 83 83 9
Birkenhofweg 3
40668 Meerbusch-Lank
Click to expand...
 
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I‘ll be visiting him in a weeks time. As I live in south of Europe I opted for the option to bring the column without the car, as I will be traveling all over Germany collecting various car parts that would not fit into the Z4 boot.
I can assure you, taking the column out on a RHD is a PITA job, my back still hurts. I had even the seat out to get more space, but still.
There is more stuff in the way than on LHD - the light module loom, the clutch pedal, the MFSW button retrofit loom.
I hope to recover my back enough to be able to sit in the car for several thousand kms.
And then again to put it back in.
 
@Straba how did the visit go? You said "I opted for the option to bring the column without the car..." - can you tell us what was the price of the repair?
 
Visit went fine, you book your slot and about 2-3 hours later it is done. They have 2 work places in parallel and when I got there another car was already in progress. He has done more than 1500 columns so far.
On LHD they take the column out blind folded, on RHD they would charge a bit more as fiddly due to the, for him, unaccustomed position and clutch pedal in the way. I can fully understand that as I have done this by myself at home and it is not a pleasant job.

He replaces the bearing with a better grade one, has custom made tools for ease of work. Also the motor worm gear gets new grease.
He was surprised my bearing was not so bad at 130k, as tried a couple of others in his crate which were really notchy when turning.
He also discovered one of the previous owners had tampered with the adjustment ring of the EPS motor, it was in the most loose position, so turned it back to factory markings.
Back at home I have put it in and tested on a road trip through the Dolomites.
I have mixed feelings about the repair. When parked outside in the sun or very hot outside I still feel as if the steering has some life of its own, definitely different then when cold. I have never driven another Z4 to compare what would be a normal behaviour, but compared to a 2019 F20 1 series and 2015 F11 5 series it feels technically inferior. After all it is BMW‘s first EPS try.
For example in a long turn you first have feedback and a force that wants to straighten the wheels, but then for a split second the force gets noticeably weaker as if in mid position and then again it is there when you finish the turn.
Maybe I have to loosen the adjustment ring a bit.
As for pricing, it is somewhat cheaper (~60% of full RHD price) when you bring the whole steering column already out of the car, but he is not comfortable with that as he wants to be sure it is done by his standards beginning to end . I had to do some persuasion and show mechanical experience spinning spanners on BMWs for him to accept. Best call or send inquiry.
 
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