Never heard of this system. Link?

I am confused when you say "right idler arm." There is only one idler arm.

Get the car on a lift and check your track rod carefully for movement. THis piece controls forward/aft movement of the wheel.
If you hit the brakes hard, you can feel a clunk if the mounts are shot. If they get bad enough, you will be able to feel the wheel actually move foward.

__________________
'90 300SE 298k
-300K and it gets put into retirement.
'80 300D 255k Purchased new by family in 1980.

Had a:
1973 220 (gas)
1980 300SD
1992 400E