A judge on Wednesday morning denied a General Motors Corp. request to put off for 60 days hearings to cancel former subsidiary Delphi Corp.’s labor contracts.

The Detroit-based automaking giant made the request for an adjournment in a letter sent Tuesday night to Judge Robert D. Drain of the U.S. Bankruptcy Court for the Southern District. Delphi, which was spun out of GM in 1999, is attempting to bring down labor costs by nearly two-thirds through the bankruptcy process.