Driving over small bumps gets loud bang from rear end

I had the same problem

could not find it out for months shocks ok GM looked at it another garage looked at it, still could not fixit, stated was spare wheel hitting at bottom of car. a friend a repair guy I know jacked up the car on my drive way one day and it bang on the left side. so he began checking it. unscrew the upper left shock bolt and found the bolt was worn about 1/4 mm you can see the shock was hitting the bolt. the shock was just jumping on the bolt at times. replaced the bolt, and made sure it was very snug ( AND IT WENT AWAY THAT WAS IT ) A WORN BOLT. IT DRIVE ME NUTS FOR A WILE. AS IT JUST STARTED ONE DAY BACK FROM THE COTTAGE

My honest opinion here is that if you took your car to someone to fix the problem and they didnt, you should really get all sorts of pissed off at the person whom told you it was fixed. They will try and get you to pay, but stand your ground and be firm. If nothing else they should give you a good discount aon their solution to the problem and let them know if it doesnt fix the problem then you will not be paying anything. I hope this gives you some guidance and best of luck to you.

Sincerely,

JC