To repair Massey Ferguson hydraulic cylinders, first use a hammer and screwdriver to remove any old sealing material from the cylinder. Then, inspect the cylinder and remove any debris or corrosion that may have built up. Use a lapping compound to remove any nicks or scratches from the cylinder. Next, use an adjustable wrench to remove any old parts that need to be replaced. Finally, use high-pressure sealant and a new seal to put the cylinder back together.