The brief
The B180 was vibrating heavily at idle, enough that the steering wheel was buzzing, and there was a distinct clunk every time the owner shifted between Drive and Reverse. A look in the engine bay confirmed it: visible collapse on the front mount.
The mounts are the rubber-and-fluid blocks that hold the engine and gearbox steady and soak up their movement. There are a few of them: one supporting the engine, one the gearbox, and a lower support that stops the whole assembly rocking. When they sag and split, the drivetrain shifts around, which is the clunk on take-up and the buzz that comes through the wheel at idle.
The diagnosis
On the lift the front engine mount was found torn and sagging, with its hydraulic fluid leaked out, and the others were no better, the rubber collapsed and deflecting past spec on each one.
Replacing only the worst one would have left the drivetrain isolated unevenly and meant a return visit when the next gave out, so the right scope was the full set, every mount holding the engine and gearbox, renewed in one go.
The work
The engine and gearbox were supported, then each failed mount removed in turn and a new Mercedes-spec replacement fitted in its place, every fastener torqued to spec in the correct order.
With the new mounts in, the engine was run at idle to confirm the vibration was gone and the drivetrain sat where it should before a road test.
The outcome
Smooth idle, no buzz in the steering wheel, and no clunk on Drive-Reverse shifts.
The B180 went home with the drivetrain isolated again. For the owner that is a car that feels solid and quiet rather than shaky and loose, and doing the whole set at once means all the mounts age together from here, instead of a string of return visits as each old one gives out.
