Just looking in Bentley. There doesn't seem to be a torque setting for the A-arms. For the upper swivel nut (top of Kingpin) The torque setting says 40lb. However, in the dismantling and reassembly instructions, it says, "Check the movement of the swing axle, slight resistance should be felt when the swivel axle is moved from lock to lock. There should be no vertical movement of the swivel axle. Add or remove shims to increase or reduce the resistance. Fit a split pin to lock the swivel pin.
My new king pin had a lock nut instead of a split pin. As I recall, I turned it tight and backed it off a quarter turn or so.
According to Haynes, the A arms also have split pins or lock nuts. Therefore, tighten and back off will likely work there also.