Labor peace returned to Detroit after the United Auto Workers voted to approve new contracts with Ford Motor Co. and General Motors Co., wrapping up one of the most lucrative rounds of negotiations for the union after it offered concessions to help the Big Three U.S. automakers get through the recession and two bankruptcies, Bloomberg News reported on Saturday. In a narrow victory, Ford’s U.S. union workers voted to accept a four-year contract that included across-the-board raises, $9 billion in factory investments and $10,000 in bonuses per member. The deal was ratified by 51.3 percent of production workers and 52.4 percent of skilled-trades workers, the UAW said on Friday. GM finally got its agreement with the union ratified without adding significant costs to the contract after revising some work rules to appease the skilled-trades employees.