Pounding Suspension ??

[Lovedabch]

I have a 1977 240D with 457, 900 miles on it. I am the original owner. I have replaced the front and rear springs; the front
(L & R) upper control arms (and ball joints) and lower ball joints.
The shocks are Bilstein (3 years old). Whenever I go over a speed bump or a road bump, I feel and hear a loud banging noise from the front suspension. I have had my mechanic check all underside parts for wear and loosenees. No luck ! Anyone got any ideas on how to get a "smoother" ride out of my 240D ??