Stiff steering and lag, 4.6is
 

Hello everyone

I replaced my lower steering shaft (part 32306762147, if you google it) and i'm still getting heavy steering and a 'lag' when the wheel is supposed to come back to centre after making a turn...
Any thoughts what else it could be? :(

(everything that could be changed on the front axle has been replaced with new parts, car feels firm on the road too and handles well.... just the steering now!! :roll eyes:)

Did you ever bring it in for a wheel alignment? Heavy steering and a lag in returning to center could be the castor alignment is off.

What he said.

Some ZF racks have a large adjustment bolt that influences stiffness. I just adjusted one on my mom's 2005 FX35 Infiniti. Worked a treat. I've read that e46 racks have the same adjustment... so I'm assuming most BMW's do as well.

I would check operation of “Servotronic” if your car were equipped with one. Every one 4.6is that I bump into had one installed from the factory. The testing process is relatively simple:
1 Tap voltmeter to the Servotronic valve wiring – easily accessible at left strut tower area. With engine, running you will be measuring 8 – 12V.
2. Using ohmmeter measure resistance of Servotronic valve (The one attached to the steering rack). I am not sure what it must read, but expect it to be no more than 100 Ohms.
3. If you don’t get any voltage reading the most probable cause is defective GM3 module. You may confirm this by supplying 12V directly to the valve. Assuming the valve is functional you’ll get very light steering. This is OK for temporally work around , but not a permanent solution.
4. If you get correct voltage, reading at the valve it might indicate defective valve itself. Valve can be purchased separately and replaced on the car.
5. The Servotronic circuit is monitored by GM3 module, so it may throw code if you scan car with BMW scanner.

^Nice catch... totally missed that it was a 4.6is.

Have you had work on your strut mounts recently? Over tightening them where the strut goes through could cause binding.

Seems the castors were off.. you guys were right :) thanks

Thanks for coming back and posting the fix. Can you go back to your first post and edit the title to add the word FIXED, so that people in the future with a similar problem can find a fix.