Suspension Beearing Bracket?
Thats a thrust bearing, I think they are inside your trans.
Now lets talk about whats wrong with your car. You need to get the tire off the ground and push/pull/inspect for worn parts.
Look at the outer tie rod ends those usually go on W126's. Also the upper and lower ball joints are problem areas on these cars.
Tell me more about this knocking sound. Does it knock going over bumps? When stopping? Do you feel it in the car/wheel? Does the car pull under braking?
what items are new, other than the shocks?

http://catalog.eautopartscatalog.com...+Rod+Mount+Kit
Be prepared to replace LOTS of bushings in your front end and the upper control arms and lower ball joints. Get a service shop to replace the ball joints because a special tool is required.
Look at the Front Axle pages:
http://mb.braingears.com/126_DISC1/p...ssis_300SE.htm
Notice the plastic hammer in the photos.:
http://mb.braingears.com/126_DISC1/p...sis/33-615.pdf
I've finished this on my 300SE and it's a big job to replace all the bushings etc. The sway bar bushing under the fuse box is a PITA but can be done without taking the booster out although the master cyl. must be removed. Might as well get a new one and new brake hoses as well.
Check all ball joint boots for breaks or tears as well as for play.
I did gathered all the information I could on this topic. And it looks like all of the above information is correct. I ordered the Guide Rod bushings..http://catalog.eautopartscatalog.co...e+Rod+Mount+Kit. Thanks for the URL. I will be installing them later this week.. I will let you know how it turns out.... thanks again... By the way, this is the my 1988 300SE



