Captain reported that a hydraulic leak was discovered on pre-flight inspection by the First Officer. Maintenance was unable to repair; so the fight crew ferried the aircraft to a maintenance base. Subsequent to the ferry flight; The flight crew was asked about the chrome extension visible on the leaking strut.

Narrative

On the afternoon of DATE; during preflight in ZZZ of what was supposed to be a ZZZ-ZZZ1 flight on aircraft X; the First Officer discovered a hydraulic leak in the left main gear. We stopped boarding; called Maintenance; and Contract Maintenance was sent out. I was asked to text photos of the maintenance logs and the hydraulic leak to maintenance; which I did. I timed out on duty period that afternoon; the flight was cancelled; and the First Officer and I spent the night with the intention of ferrying the aircraft out in the morning. In the morning; I sent photos of the logs to Maintenance; spoke to Maintenance about specific operating actions (there were none); signed the ferry permit; and then we did our preflights; de-iced and continued to an uneventful flight and landing in ZZZ2. ZZZ station did a great job throughout the entire event; handling the crew members; Contract Maintenance; and upset passengers very professionally and cheerfully in the middle of a lot of snow. On DATE1; the First Officer and I received an email from our Fleet Manager regarding this ferry flight and asking about the amount of visible chrome on the main gear. I referenced the photo of the gear that I had earlier sent to maintenance and estimate it to be about two inches of visible chrome- within tolerances for our pilot preflight. I don't recall specifically if that was the case the next morning before we ferried the aircraft; but I do remember looking at the gear in question before we boarded; and I think that I would have noticed if it were much different than the previous night. After our email correspondence; I decided to do an report in case there's something in question regarding our preflight action. A good reminder for me that in the event that a maintenance issue spans overnight; I should clarify with maintenance that nothing has changed from the night prior before departing in the morning.