How to replace drive belts in Mercedes 420sel?

To replace the drive belts in a Mercedes 420SEL, first, ensure the engine is cool and disconnect the battery. Loosen the tensioner pulley to relieve tension on the belts, then remove the old belts by sliding them off the pulleys. Install the new belts by routing them according to the belt diagram typically found under the hood, and then adjust the tensioner to ensure proper tightness. Finally, reconnect the battery and start the engine to check for proper operation.