Pull the steering fuse on Z4
Discussion
I unpluged the EHPAS on my mk2 MR2. Steering was heavy at parking speeds but excellent when moving.
I did it because the system had a leak and the assistance would cut in and out at random - it was safer to drive with it disconnected until I fixed it.
None of this relates directly to Z4s though.
I did it because the system had a leak and the assistance would cut in and out at random - it was safer to drive with it disconnected until I fixed it.
None of this relates directly to Z4s though.
FlavaDave said:
It would be great if you could 'tune' the assistance.
Some cars you can. The wife's old Punto had a button which lightened up the steering for parking (not that it seemed to actually serve any real purpose, given how light the steering was anyway). Doesn't really help with steering feel though, just changes the weight.
LuS1fer said:
Just roll the car down a hill with the ignition on (to avoid the steering lock engaging)but not having started the engine. You'll soon get why it has to be power steering when you have wide tyres.
I know it will be stiff. But this thread doesn't ask "Why does my car have power steering?" ;-)FlavaDave said:
LuS1fer said:
Just roll the car down a hill with the ignition on (to avoid the steering lock engaging)but not having started the engine. You'll soon get why it has to be power steering when you have wide tyres.
I know it will be stiff. But this thread doesn't ask "Why does my car have power steering?" ;-)AJB said:
LuS1fer said:
Just roll the car down a hill with the ignition on (to avoid the steering lock engaging)but not having started the engine.
But be VERY aware that, once the vacuum reserve runs out, the brakes will pretty much stop working....Even with the fuse pulled, most pure EPAS racks/columns still give relatively poor steering feel simply because the worm and wheel and motor that provide the assistance act like a friction damper; introducing some stiction and filtering out a lot of the steering feedback.
The other issue is that you typically have a torque sensor which uses a very thin (maybe only ~5-6mm thick) shaft to connect the rack to the column (with within the column), and sensors detect the twist in this shaft to determine how much assistance to apply. The maximum angle you can twist this shaft is limited by mechanical stops, but with no assistance this introduces a small angle of steering wheel movement where the wheel is not solidly connected to the rack.
Hydro-electric racks are better, but still have the torque sensor which is why using a hydraulic rack as a non-assisted quick rack is a silly idea.
The other issue is that you typically have a torque sensor which uses a very thin (maybe only ~5-6mm thick) shaft to connect the rack to the column (with within the column), and sensors detect the twist in this shaft to determine how much assistance to apply. The maximum angle you can twist this shaft is limited by mechanical stops, but with no assistance this introduces a small angle of steering wheel movement where the wheel is not solidly connected to the rack.
Hydro-electric racks are better, but still have the torque sensor which is why using a hydraulic rack as a non-assisted quick rack is a silly idea.
Edited by Mr2Mike on Wednesday 18th July 17:33
When our PAS failed on our mini cooper S (common fault) my missus found the car undrivable and couldn't park it because of the weight. She got a colleague to park the car out of the way. When the rescue truck turned up, i had been dragged into the situation and the steering was pretty similar to my current vw T25 campervan at parking speed. Ie. it was a bit of a workout!
Mike
Mike
Gassing Station | General Gassing | Top of Page | What's New | My Stuff