I've noticed that during the winter months when the temp get down around 40 or lower, in the morning when I head to work I can feel the steering wheel making little bumps or pops when I turn the wheel. It's not smooth like it's supposed to be.....if I go full lock to lock, I can feel something pop a few times. I can't hear it..but I can just barely feel it.

After I drive the car to work and everything is warmed up, it's all back to normal. I can turn lock to lock and it's nice and smooth. I recently replaced all the bushings in the front end, upper shock mounts, and shocks....and it's still doing it. Could I be getting air in the power steering system?

Any other ideas? It just feels kind of jerky/gritty in a few spots as I turn the wheel. Only when cold....after everything warms up it's fine.

Thanks

 

The system runs at pretty high psi...so if the ps fluid tank is full, air should not be an issue...
Might be worth changing the fluid using the proper petrosin ps fluid....or even a partial change.

 

Could dirty fluid cause this? What's the best way to flush the system?

 

My experience is that crunchy steering is caused by the U-joints/bearings in the steering column (I assume that you are parking in the cold, is that right?). Try pulling down the knee bolster, removing the column shrouds, and lubricating the mocing parts. I have used a spray lithium in the past with pretty good results. On my car at least, the spot that requires the lube is high up (not the joint down by your toes), and to get at it requires putting your head down in the footwell and looking back up along the column.

 

To flush it you would just drop a hose, drain, refil...
then turn the wheel to the stops a few times to bleed....but it might ne simple to just drain or sipon off as much as you can from the resivour, then refil....kinda freshen the fluid, reduce the level of contamination. Flush be better, but changing out half the fuild may be enogh to help lengthen the pumps life....heck it is syenthic fluid, but heck, after many years of use, i bet new is better!!
agree on the ujoint suggestion above, might be the actual issue...might be just at the start of having a dry joint...a turn or two moves the lube around...and all is good!!

 

IQ Raceworks,
I used a Turkey Baster and sucked out the fluid when it was cold; refilled to the correct level and drove the Mini a bit. Returning home I did the same again once the fluid was cool, I did the above method 3 more times. Easy to do with almost no mess. Just make sure the level is correct once the fluid is warm. Use the correct fluid only !

 

Thanks for all of the info guys. I got up under the dash last Friday and sprayed the u-joint connection with some white lithium grease. I worked the wheel back and forth several times, and it seems to have helped a little. I think I'm still going to flush the system out with some new fluid though...probably can't hurt. I just need to go by the BMW place and get some...no other place around here carries that special fluid.

Maybe after the grease works it's way in it will go away.....but it still seem to have that crunchy feeling every now and then. But once I've been driving for a while, it all goes away.

One thing that I did notice though.....if the motor is off (no power steering), I can turn the wheel lock to lock....and I don't get the crunchy feeling. I only get it when the motor is running, and the electric power steering pump is helping out.