The bearings are replaceable, here is a DIY.
http://www.peachparts.com/Wikka/W123RearWheelBearings

Those bearings don`t look good. I pulled both Trailing Arms off a 85 300CD in PNP last year for the up grade on our 85 300D. I paid $42 for ea arm with the hubs. maybe $250 was for shipping and the parts.

Either replace the bearings or find some lower milage arms. the W126 first generation (81-85) will also fit the W123.

Pressure wash the arms at one of those 25¢ DIY car washes. mine had that Cosmoline waxy stuff on them and I wiped them down with paint thinner (Mineral Spirits). I use POR products, so used the Marine Clean for a final degreasing, sanded and applied 2 coats of the POR paint.

since you are this deep into the project, good time to replace the trailing Arm bushing and Sub frame bushings, and Diff mount.

If the car is a rusted old beater, may not want to do the additional work.

Charlie

__________________
there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works