After noticing a romp romp romp sound from the rear, I decided to tackle changing the rear wheel bearings. I bought OEM bearing from the dealer and removed the rear knuckle assemblies, dropped them at the local machine shop to have the bearings and hubs removed and pressed back in.

This is not an easy job since Mercedes uses a 5-link rear suspension. That means that there are 5 connections, plus the sway bar. Each each has to be removed and then using a puller, press the knuckle off the drive axle splines.

When reinstalling, you need to lift the rear suspension to ride height before torquing down. I measured mine which was 14.5 inches from center of wheel to wheel opening. Then, when reassembling, leave everything loose until you put a floor jack under the hub and lift it into ride height position. While I was there, I replaced both rear Airmatic shock assemblies as the air springs were replaced a few years ago. I used Arnott rebuilt units. These are a lot of work to change as the entire trunk paneling has to come out to get access to the upper shock mount.

https://www.rockauto.com/en/moreinfo...&pt=7556&jsn=1

When I removed the knuckles, I pulled the E-brake parts off. The shoes were like new so I bought new hardware. Nothing is made to high standards today and I ended up cleaning up the threads of the adjusters with a tap since the threads were not "clean" on the hardware that I bought. Reattaching the E-brake at the adjuster unit under the vehicle is a real PITA. But, it is done.

Vehicle drives quiet now, no more romp romp romp sound.