If your 850 feels a little vague and floaty then the front Track Control Arm (TCA) inner bushes may have worn out. If you have someone watch the front wheels whilst you 'nudge' the car backwards and forwards using the clutch and footbrake and the wheel seems to kick back and forth attention is most likely required.
First jack up the front corner of the vehicle on the side wish to work on and support it with an axle stand beneath the subframe or under the chassis far enough away from the TCA so it doesn't get in the way.
Remove the road wheel to gain access to the TCA

This is the front most bush....

...and this is the rear.