Another power steering module failure

[Jim28270]

Hi all

My z4’s been off the road for the last few months owing to the well-known power steering motor/module failure. Fault was intermittent to start with but now permanent, with sport button also dead. I plan to work on this over the next couple of weeks.

The driver’s seat is out and lower trim is removed. Having had a good look at the column, I’m now in desperate need of some guidance on best procedure to follow from here, if anyone can help? Photos attached below.

I think I understand the basic process - loosen the eight bolts holding the steering column brackets to drop the column slightly, unplug electrics, mark alignment of the motor/steering column/spacer, remove the two torx bolts securing the motor to free the motor and send off for repair. But I have a few question on points where previous threads seem to give conflicting advice.

• do I need to remove the steering wheel and/or remaining lower trim? As far as I can see, the lower dash part that would actually be helpful to remove is not removable. Does the steering wheel shroud need to come off?
• do I just loosen the 8 bolts holding the steering column brackets, or do some of them need to be removed? How far to loosen?
• after loosening the brackets, do I have to rotate the column/motor 90 degrees so that the motor is pointing down? I cannot see how there is space for this. Equally I cannot see how there is space to remove the motor without doing this. Does the narrow horizontal piece of trim in the first photo need to come out?

Any advice much appreciated. I’m desperate to get back on the road for the summer.

 

[bigwinn]

@enuff_zed is the master and can give you the best tips on this

I always end up with skinned knuckles

 

[enuff_zed]

@enuff_zed is the master and can give you the best tips on this

I always end up with skinned knuckles

And as if by magic................. I'm here.

I remove the steering wheel as once you have the motor out it is fiddly to extract yourself from the footwell.
I remove the lower shroud and the lower panel in the footwell.
I don't touch any of the column bolts at all? Just unbolt the motor and wiggle it out. Otherwise you have to cut that section of dash out and even then it's a sod to get the motor out.
Due to access you can't really get a socket in there, but an 8mm bihex ratchet ring spanner works perfectly. It isn't cranked like a normal spanner so fits neatly into the gap.
Adjust the column fully rearwards and down for better access to the front bolt.
Mark everything up as you said. When the motor is off, scratch the mark on as well, in case it gets cleaned off.
The big power plug faces downwards and is easy to remove. The two above it are difficult to see. So have a pair of snips on hand. Once the bolts are out, pull the motor outboard and turn it so the worm drive comes down first. The Torque Sensor cable is cable tied to the motor and doesn't allow it to quite reach the floor. Snip the ties and let the worm drive rest on the floor while you unplug the other two unplugs.
Note how the Torque Sensor cable is routed. You don't need to put ties back on it as long as it is routed correctly and isn't pinched.

If your car is a manual then you also need to depress the clutch pedal to clear the motor. I put a rag on it and use the back of my head. You could probably tie it down to the clutch stop?

When you put it all back together don't worry about aligning the marks until the bolts are nearly tight. It's only the spacer that needs moving; the motor bolts to the column and can only go in one place.
The bolts are fiddly to get started, so lift them into place using the ratchet ring spanner and once located, apply pressure to the bolt head with a screwdriver blade.

Any problems, PM me your mobile and I can help via a Whatsapp video call.
With a replacement motor to hand I can now do the whole job in around an hour.

 

[Jim28270]

@enuff_zed, that’s brilliant, thanks. If I understand correctly then, there’s enough space to the right of the motor to withdraw the motor in that direction, then bring it out towards the engine and down. Nice approach to clearing the clutch pedal, btw.

I’ll give this a go next weekend and report back. I’ve just tried getting the steering wheel off. The airbag assembly came off very easily but the thread locker on the 16mm column bolt is proving stubborn. I’m a bit worried about overdoing it and breaking the steering column lock. Any tips?

 

[enuff_zed]

@enuff_zed, that’s brilliant, thanks. If I understand correctly then, there’s enough space to the right of the motor to withdraw the motor in that direction, then bring it out towards the engine and down. Nice approach to clearing the clutch pedal, btw.

I’ll give this a go next weekend and report back. I’ve just tried getting the steering wheel off. The airbag assembly came off very easily but the thread locker on the 16mm column bolt is proving stubborn. I’m a bit worried about overdoing it and breaking the steering column lock. Any tips?

They can be tight but only need one good crack and then it’ll spin out easily. Given that the steering lock is designed to stop people breaking them by yanking on the wheel rim, I think you’ll be fine.