You're going to have to Google "Thule Volvo 850" and find available towers and fit kits, etc via ebay or Amazon. Thule or Yakima don't make them any longer. Find a set of towers, and then search for the proper fit kit for them (I'm away from home, so I can't dig up the parts on our cars.) ...

Look up Traverse or 400XT foot packs. (Ours are the 400xt) The fit kit for the 400xt is 161 Not sure about the Traverse. (They may not have done a Traverse one for the 850) These are square bar kits. Yakima Q-towers with Q51 clips is another option (round bars) Googling the 400xt and the 161 fit kit...

I had to have the alignment re-done as it was done by the dealer on a 4 wheel system they found the LHS rear was out of alignment. As to why it was out, I have no idea, but I had to have the adjustment part replaced as it had frozen. Good old aluminum and steel together and salt on the roads in wint...