Mercedes: 1985 MB 300SD - Front Suspension, control arm bushing, 300sd

Question
I just purchased a nice diesel in hopes of having a reliable car with better fuel economy.  Drove it home from Dallas today for a total of close to 600 miles.  Hummed right along.

I do have a concern that I'm hoping you can help me narrow down.  Whenever I hit a bump, there's a knocking noise from the front suspension.  I thought maybe a bushing was worn out or something.  But, I can't feel anything that seems loose.

Can you point me in a direction to check?

Answer
Answer:

Suspension Bearing Bracket guide rod mount replacement
on the 1985 300SD
http://www.mercedesshop.com/Wikka/W126GuideRodMount



Guide Rod, Lower Control Arm Bushing and Eccentric Pin Replacement on the 1985 300SD
http://www.mercedesshop.com/Wikka/W126GuideRod