Hopefully someone can help with this one. I was mowing and hydraulic line busted. The only way I knew is the left side started locking up. I put the mower in free wheel with the dump valves and the side that was locking up will not free wheel. I changed the line added oil and when I try to move forward I go about 3 feet and it stops on the left side. It will go fine in reverse on both sides, forward on the right side. Do you think there is air in the system or did I cook the drive motor? Thanks. This is on an old scag zero turn mower.