However the FastLane part is cheaper, and they support this forum.
This is the perfect time to replace the lower control arm bushing and Eccentric Pin.

Loosen the front wheel bolts.
Raise and support the front end.
Remove the front tire.
Remove the spring, special spring compressor required.
Remove the lower shock absorber bolts.
Separate the lower ball joint from the lower control arm.
Mark the position, and remove the Eccentric Pin from the lower control arm.
Separate the lower control arm from the body.
Remove the lower spring seat plate from the lower control arm.
Remove the Guide rod to control arm mount bolt.
Remove the lower control arm from the car.
Remove the Guide rod mount bushings, and clean the mounting area.
Remove both of the inner control arm bushing caps.
Drive out the old inner control arm bushing.
Install the new inner control arm bushing.
Install the new inner control arm bushing caps, (a heavy thread or light fishing line works well).
Insert the guide rod into the lower control arm.
Use a floor jack to press the inner lower control arm into the body.
Use a large tapered punch to align the
Install the Eccentric Pin into the lower control arm, align it to the mark and tighten.
Install the Guide rod mount bushings.
Install the Guide rod to control arm mount bolt. (use LoctiteŽ thread adhesive)
Install the lower spring seat plate to the lower control arm. (use LoctiteŽ thread adhesive)
Install the spring, but do not release it yet.
Install the ball joint, and tighten. (use LoctiteŽ thread adhesive)
Install the lower shock absorber bolts. (use LoctiteŽ thread adhesive)
Release the spring compressor, and remove the tool.
Install front tire, and snug (best possible) wheel bolts.
Lower the car.
Torque all wheel bolts.

As an FYI, here are related W126 front suspension procedure DIY data links.
Suspension Guide Rod Replacement
on the 1985 300SD
http://www.peachparts.com/Wikka/W126GuideRod
DIY Guide Rod replacement for Mercedes Benz 300SD.
http://www.peachparts.com/shopforum/showthread.php?t=92874


PART NUMBER SEARCH RESULTS WITH PRICES
Vehicle 1986 Mercedes Benz 420SEL
Part: Guide Rod Repair Kit
Note: Guide rod to control arm
L2070-16062 Guide Rod Repair Kit Lemforder IN STOCK

http://catalog.peachparts.com/item.wws?sku=W0133-1631144

PART NUMBER SEARCH RESULTS WITH PRICES
Vehicle 1986 Mercedes Benz 420SEL
Part: Control Arm Bushing Kit
Note: lower inner
L2040-16578 Control Arm Bushing Kit Lemforder IN STOCK

http://catalog.peachparts.com/item.wws?sku=W0133-1624590


PART NUMBER SEARCH RESULTS WITH PRICES
Vehicle 1986 Mercedes Benz 420SEL
Part: Eccentric Pin Kit
Note: lower inner control arm
L2043-25529 Eccentric Pin Kit IN STOCK

http://catalog.peachparts.com/item.wws?sku=W0133-1624360