Mercedes-Benz W126 rear wheel bearing
My W126 whines from the rear at high speed - has the rear wheel bearing failed?
A shrill whine at high speeds often points to the rear wheel bearing. Check by lifting the rear wheel with a jack and testing for play. A broken handbrake return spring can cause a scraping noise like a bearing.
What tools are needed to replace the W126 rear bearing?
The driveshaft is removed, and opening the large locking nut of the hub requires a special socket with an outside diameter of 55 mm. A guide with a 27 mm pin keeps the socket from slipping. The nut can also be opened with a four-pin special wrench.
How is the rear bearing replaced and tightened on the W126?
The old bearings are driven out and the new ones installed with attention to the seals; petroleum jelly is added to the bearing. The preload is adjusted with the crush ring to the correct play, because tightening too hard overheats the bearing. The collapsible spacer is replaced with a new one. The wheel bearing is safety-critical, so have a workshop check the work.