Here's what I do,Assuming your assembly is still in the car?
There are three bolts that hold the spring bracket to the pedal support I remove two of them and loosen the third.I then put the spring on the pedal,I swing the bracket towards the pedal which gets it close enough to put the spring on.Now I use a small hardened punch or thin screwdriver placed through one of the holes I took a bolt out of.I pry the bracket into position until the other bolt hole lines up,I install that bolt,remove my punch install the third bolt and I tighten them down. That works for me everytime.Y
ou could always try grabbing the spring with a pair of vice grips and yank it back into place ,It sucks when the spring slips which it will.Ask me how I know.LOL.......Good luck.