On my 1976 Cessna 150M, My left rudder return spring is broke as well. I bought the new spring, part number 0310196-13. Got the end hooked on to the clip that is attached to the control cover, but cannot find where the other end attaches at.
The only place that looks plausible is the tab that comes up off the bar and has the cable attached to it. On the forward side of that piece is a tab that bends slightly toward the pilot side and has a hole in it. It just seems like that would be too far for the spring to be stretched with the rudder pedals are in a neutral position.
I have referenced the IPC - page 152 / Figure 61, and the 1969-1976 Service manual Section 10, figure 10-2, but both illustrations are facing from the forward pilot side and only really depict the right rudder return spring mechanism which is on the pilot side interior of the control cover. I am unable to find illustrations or drawings on the left spring on the co-pilot side.
Any help appreciated.