Getting clunk type sound when braking hard

Strut rod loose?
Finally got a chance to take my car out to test it out after tightening the strut rod on the drivers side that was not tightened very well originally by me and after my 13 year old son and I bled the brakes. Brakes work great now and no more clunking noise. I did have an issue driving at around 40 MPH and all of a sudden I had no power. Lost all lights and was able to pull over to a safe area. Popped the hood and called AAA. After I arranged to have a flatbed pick me up I thought back to my younger days driving my 68 Impala and it would just die exactly like my car did. It was a bad ground. I checked my battery connections which are tightened down good. I moved the cable part which is clamped on with the correct type end and then when I turned the lights on they came on. Got in and she fired up. Closed the hood and started driving home. Called AAA to cancel and the guy I talked to said...How cool, I have a 72 340 Duster. He saw that I had a 70 Duster. I'll check things better and maybe even find an original type ground cable to install this week.