Scary/Twitchy feel over 65mph!

[mjennings23]

As another perspective on this, my steering was wobbling a bit at 65 after a full alignment.

Due to unrelated issues, I believe, the EPS also failed a few weeks later, and I've since replaced the rack with an E46 hydraulic system, detached the EPS motor and replaced the intermediate shaft with the Z4M part.

No more wobble.

Now, I don't know if it was a worn out UJ on the intermediate shaft, a worn gear in the rack or just the electric motor trying to correct but I'm far happier with how the car feels now!

 

[Sky-drive]

As another perspective on this, my steering was wobbling a bit at 65 after a full alignment.

Due to unrelated issues, I believe, the EPS also failed a few weeks later, and I've since replaced the rack with an E46 hydraulic system, detached the EPS motor and replaced the intermediate shaft with the Z4M part.

No more wobble.

Now, I don't know if it was a worn out UJ on the intermediate shaft, a worn gear in the rack or just the electric motor trying to correct but I'm far happier with how the car feels now!

... is replacing the electric system with a hydraulic system a major undertaking? Im guessing it was a fairly expensive mod?

 

[mjennings23]

As another perspective on this, my steering was wobbling a bit at 65 after a full alignment.

Due to unrelated issues, I believe, the EPS also failed a few weeks later, and I've since replaced the rack with an E46 hydraulic system, detached the EPS motor and replaced the intermediate shaft with the Z4M part.

No more wobble.

Now, I don't know if it was a worn out UJ on the intermediate shaft, a worn gear in the rack or just the electric motor trying to correct but I'm far happier with how the car feels now!

... is replacing the electric system with a hydraulic system a major undertaking? Im guessing it was a fairly expensive mod?

Probably less than you're expecting, it's 90% just parts from the E46. The only hard to find part is the Z4M intermediate shaft, seems very rare used here and £250 new from Sopers.

For perspective, I did my job for around £450 including the following:
Refurbished rack £140
Refurbished pump £75
Used pipes, no leaks £50
Z4M used intermediate shaft £65
New belt £8
Various bolts (I installed all new bolts and clips, possibly not needed but I figured I may as well), new pump pulley £45

If you were to buy all new parts, it would be significantly more expensive, I believe the pipes alone new come to around £200, a new rack is close to £1000 I believe?

Did all the work myself at a reasonable pace over one weekend. Started at 1pm on Saturday, worked until 7 and then another 4-5 hours Sunday finishing it off, so certainly DIYable if I can do it on the driveway!

Now my reason for doing it was due to the EPS failing on me, I figured the price differential between having the EPS refurbished and replacing with hydraulic was small, so why not make the improvement.

 

[Joycey]

Well tonight I replaced the tie rods and took the intermediate shaft out to have a look. This means all that's left is the rack itself. Will test drive later this week. If its still doing it I will send the rack away to be rebuilt.

 

[Anonymous]

This fix was from another guy on the Z4 Roadster forum, but I couldn't find the link to re post here, maybe there is already a write up on it.

If anybody else is having the same issue, try adjusting the eccentric ring between the steering motor and steering shaft. The bottom of the ring needed to move towards the drive (top of the ring towards the engine) so anti clockwise when looking towards the motor, or clockwise when looking towards the steering shaft.

This can be done without taking the steering column out, but you'll need a T10 spanner, a T10 socket, a ratchet knuckle and ratchet extension.

This fully solved my issue with the twitchy steering, it's trial and error how much to move it. Firstly I tried rotating the ring the opposite direction which made the steering feel more direct but definitely introduced the 'sticky steering' problem and was still twitchy over 30mph.

Here's an image of it rotated the "wrong way" for the issues I had, I eventually rotated it the opposite way to this.

 

[Joycey]

This fix was from another guy on the Z4 Roadster forum, but I couldn't find the link to re post here, maybe there is already a write up on it.

If anybody else is having the same issue, try adjusting the eccentric ring between the steering motor and steering shaft. The bottom of the ring needed to move towards the drive (top of the ring towards the engine) so anti clockwise when looking towards the motor, or clockwise when looking towards the steering shaft.

This can be done without taking the steering column out, but you'll need a T10 spanner, a T10 socket, a ratchet knuckle and ratchet extension.

This fully solved my issue with the twitchy steering, it's trial and error how much to move it. Firstly I tried rotating the ring the opposite direction which made the steering feel more direct but definitely introduced the 'sticky steering' problem and was still twitchy over 30mph.

Here's an image of it rotated the "wrong way" for the issues I had, I eventually rotated it the opposite way to this.

20171013_175900.jpg

Nice one, I actually found this out the hard way by removing the whole rack. Got my steering feel back to what it should be!

 

[Kamuela]

There're a couple of write-ups on that, including one on Bimmerforum that I put there, but I can't seem to find them right just now. When I got my Z I was aware of the potential for the steering issue to surface after a while but I didn't expect it to be as bad as it was; in fact, the seller must have known because they kind of expressed surprised interest later that I had dealt with it and hadn't come after them with a hammer. It affected the selling price, I'm sure. Ha. Showed them. I knew about the drill-and-grease thing, which did f#$k-all, and my stealer wanted something like $8k for a steering column. Swore I was the only person in history ever to experience the problem, the lying bastard. Same with pretending to lube the u-joints, which was more of a pain in the arse than I imagined it could be and did diddly squat. When Guido K posted about the German website, with 120+ pages devoted to fiddling with the tension ring, I found the cure.
For those in the US, it's a bigger pain because of the knee airbag; can't get to one of the bolts without removing the airbag first, then it's a piece of cake, relatively. It also takes a 6mm hex head on this side, not the Torx driver. Somewhere up in my dash is the ball from my ball-end hex wrench, too; those bolts are snug!
I ended up rotating the ring about 14mm as measured between witness marks. Some have expressed concern that going too far will make the steering "light"; I don't see how. Increasing the lash just means the worm takes a fraction longer to engage the wheel, and since it's near-instantaneous response from the motor, it's not going to affect the overall steering response. Too tight, which seems to be the problem, causes a bind.
Anyway, even with removing the airbag and vacuuming the floor mat I'm going to lie on, it's less than an hour's work.

 

[Mr.President]

Sorry to bring up an old thread but i have the same problem.
My coupe just felt dangerous when driving at 150 kmh, it was moving left and right. At first i thought the problem were RF tyres but after changing them the car behaved the same at high speed. After adjusting the tension ring the car feels much safer but the problem is not gone.
Atm i am at a 4 day car event in Croatia at which we were driving on highway under police escort and i wasnt comfortable driving at speeds higher then 180kmh, this weerd left then right movement is especially shown when i enter slight bends at high speed.
The alignment seems to be fine, my mechanic cant find anything else to be wrong with the car, the tyres are new staggered 18s and the car acts the same on 17s, and the coupe only has 47000km on the clock.
I have driven a lot of cars and also some real shitty ones like lada samara ( russian car), and i have never felt this unsafe at high speeds.
If i wont be able to find the problem soon, i think i will have to sell it

 

[Jembo]

Sorry to bring up an old thread but i have the same problem.
My coupe just felt dangerous when driving at 150 kmh, it was moving left and right. At first i thought the problem were RF tyres but after changing them the car behaved the same at high speed. After adjusting the tension ring the car feels much safer but the problem is not gone.
Atm i am at a 4 day car event in Croatia at which we were driving on highway under police escort and i wasnt comfortable driving at speeds higher then 180kmh, this weerd left then right movement is especially shown when i enter slight bends at high speed.
The alignment seems to be fine, my mechanic cant find anything else to be wrong with the car, the tyres are new staggered 18s and the car acts the same on 17s, and the coupe only has 47000km on the clock.
I have driven a lot of cars and also some real sh***y ones like lada samara ( russian car), and i have never felt this unsafe at high speeds.
If i wont be able to find the problem soon, i think i will have to sell it

Welcome to the forum... standard Z Steering is notorious, had the issue on my old 3.0 which I never totally resolved. This thread with the eccentric ring adjustment under the dash appears to have the greatest of success. Good luck