This if often a symptom if a steering gear box that has been over-tightened.
Try re-djusting the steering while on center so that the binding does not occur. If I recall correctly, up to 25mm of play is permissable when the steering wheel is centered. It is VERY important to not over-tighten the adjuster. You are looking for a balance between free-play and removing the play.
I have never seen a "frozen" component, such as a tie rod end or
ball joint offer these types of symptoms.
If all else fails, you can also simply replace it.
Keep us posted,
'03 E320 Wagon-Sold
'95 E320 Wagon-Went to Ex
'93 190E 2.6-Wrecked
'91 300E-Went to Ex
'65 911 Coupe (#302580)