Generally, you will tighten the fittings as much as you can with normal hand tools. If you then do a test after installation by starting the vehicle, check for leaks at the fittings. If you notice even a a drop of fluid leaking out then you will need to tighten them down further. Heat can make the metal expand so checking for leaks is important.
in the video I have linked you will see our installer using regular wrenches to tighten down the hardware. Notice that he is making the fittings... view full answer...
The Curt Trailer Hitch Receiver - Custom Fit - Class II - 1-1/4" Item # C12009 for the 1996 Buick Roadmaster installs without need to lower your exhaust but does require some drilling. All required hardware is included. Tools needed for installation include 15mm wrench and socket, 3/4-inch socket, drill with 9/16 bit and a torque wrench. I have linked a helpful article concerning hitch installation tips. view full answer...