with the way that looks, you'll want to go ahead and replace them all now..
you or somene else will be driving and the brakes will go out..
It'll be easier if you replace them all now... because you can remove them all, then install them from right to left, and there will be no lines on the left getting in your way limiting your wrench turning space.
IMO it would be foolish not to do it all at once.. to repair one only to have another burst soon.. doing it the hard way, when you can do them all easier. The nuts are hard to find if they are the 5/16 with the 1/4 bore which i think they are.. so i'd suggest getting the preformed kit. I went the easy bend route and now i can't find the nuts.. i'm about ready to buy the preformed kit and pull this easy bend back out. My truck has been down way too long dealing with it.. luckily i have backup vehicles. As a matter of fact thats' why i'm here to see if anyone knows where to find the gdam nuts.