fixing the line yourself is doable but it depends on the leak's location. If it's a simple easy-to-reach split patching it up with new tubing and connectors should be straightforward. However if the leak is hidden or the line is damaged throughout it's a more complex repair, potentially requiring removing parts of the car. If you're handy and can easily see the leaktry fixing it yourself. If not, or if you're unsure of the line's path it's best to have a professional fix it.