If I have no obstructions, and the right tools, I can change out pads, and rotors on a w123 in slightly over an hour (with NEW bearings), and I'm NOT a mechanic. Can't imagine a 124 taking much longer (I'm assumming it's a 124, right? Try putting more info in your signature). Do yourself a favor and hang out while he does it. Brakes are one of those things that I don't understand why more people don't do it themselves. Very easy work.

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1989 300E 144K