its not real easy, but not imposible. Its best to perform while doing a transom plate rebuild. Take a good look at the bellows, water hose, shift cable, gimbal bearing and any other part of the transom. If they need to be replaced, now is the time. If they all look good, loosen the hose clamp holding the water hose onto the water tube(on the inside of the boat, it may take some work, but remove the hose from the tube. Now remove teh 2 screws holding the retainer plate in place(item # 29) Remove teh rubber bushing(item # 28) and slide the water tube out thru the back using the water hose as a pull handle. I don't remeber if I have ever replaced the tube with out replacing the bellows(transom plate rebuild). Its not an easy job, good luck with it. Make sure your not getting water thru from a corroded outer plate, move the water hose out of the area it rest in and look to see if its corroded behind the hose. PM me if you have any questions