Brake vibration and front wheel bearings

[ATLD]

Gentlemen,

A few questions regarding my recently acquired 86' 560sel. I find that I get a noticeable vibration in the vehicle when braking medium or hard from 30+ mph. Assume this is not normal so replaced front and rear rotors, pads all round, rebuilt calipers, replaced pads with organic, flushed the brake fluid, and pressed in new front bearings etc. The vibration still exists.

I guess my question is twofold:

1) Regarding the front bearing preload. Can anyone go over the procedure? I first noticed that there is no washer between the front out-board bearing and the lock-nut; none on either wheel. None came with the bearing kit. Should there be one? Some of my other German cars have one. Anyone know the p/n? When I set the preload, I cranked down on the lock-nut when rotating the rotor until the resistance was significant, then backed off 1/3 turn. I could not procure enough preload to get the rotor to stop completely like I could on my 123 diesel. Is this normal? It seemed to require excessive torque to turn that lock-nut sufficiently to get this bearing drag. My worry is that there should be a washer and I am bottoming out the threads on the spindle, without achieving proper preload. Any thoughts?

2) With the rotors, pads, calipers and bearings all replaced, what else could cause a significant vibration when breaking only. Could it be the tires? They don't cause vibrations when accelerating and/or when cruising at speeds.

Thanks,

Adam