On eBay the Baum Tool brand bearing remover and installer is $282 part number 1240543. Note I searched for Mercedes W124 rear bearing tool.

Note also on eBay there is the same tool cheaper around $55 listed as "Mercedes-Benz Press Rear Wheel Bearing Hub Remover Install Axle Bush Puller Tool" it has unbranded made in China

That brings up the question is Baum Tool also selling a Chinese one?

Amazon also tends to sell the same items.

And if someone was willing to go through the trouble to re-sell it after the job you could recovers some of the tool cost.

With the tool someone could change both of the rear wheel bearings if that is what you wanted to do.

Another method would be to remove the Knuckle and take it to an automotive machine shop and let them remove the bearing and install the new one.

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84 300D, 82 Volvo 244Gl Diesel