The bolts that hold the spring locators are, as previously mentioned, 'captive'in that the heads are welded in place inside a box=section of the chassis---very difficult to get at.The easiest way to get the nut off is by using (VERY carefully) a 'power-file'---these have narrow belt-sanders on them. File away one side of the nut until you JUST see the thread of the bolt. If the bolt's thread is only damaged over a very short section you (a) might find that running a die over it will clean it up enough or, (b) as there is a fair length of spare thread, you can put a spacer over the damaged section when refitting the spring which will cover the damaged thread and put the new nut onto clean thread. Whatever method you use to remove the nut, be very, very careful because replacing the bolt is NOT an easy task!