PA28-180 pilot reported an oil line break during a maintenance flight check. Pilot executed a return to the airport and made a normal landing.

Narrative

Aircraft had been in Annual Maintenance; with new fuel gauge system installed. During takeoff and passing 300 feet my right seat pilot stated that oil was dripping onto the left rudder pedal on the right side. I turned a crosswind leg and decided to land quickly. Two Cessna 172 had entered the pattern so I told then that I [requested priority handling] and requested they exit the pattern. They did so. I made a short approach and landed safely. Approximately 4 to 5 Oz. of oil was noted on the right floor pan. The carpet had to be replaced. Upon inspection the oil pressure line had broken at the firewall. We were shown the broken tube and also a photo of the Manifold Pressure line. It was in the same condition so we requested that it be replaced at the same time. This was done and the operational check showed the problem solved. The airplane was manufactured decades ago and apparently the corrosion had not been previously noted.I am glad that I had a second pilot in the right seat as it may have bee some time before I noted the lack of oil pressure.