Abstract: The hydraulic pressure relief tool opens a check valve in the male portion of a hydraulic line coupler. The male portion has a locking ball receiving groove. The tool includes a male coupler holder and a coupler retainer that are pivotally connected together. The male coupler has a U-shaped groove. The sides of the groove slide in the ball receiving groove. The male coupler engaging surface on the retainer is moved across the U-shaped groove to lock the coupler to the tool. A fluid deflector housing covers a portion of the U-shaped groove. A check valve opener is mounted in a threaded passage in the housing. A valve engaging surface on the opener is advanced to open the check valve.