[Healeys] Overdrive relay

[BJ8 Healeys]

Hello, Healeyphiles -
 
Just curious if anyone has ever taken apart an overdrive relay and
understands the function of the piece that is attached to the upper end of
the coil and zigs around to "restrain" the moveable contact in the opening
direction?  
 
I have a used relay and a brand new Moss replacement (Made in the UK!) that
works the same way out of the box.  I am not getting a "latching" function
to hold the overdrive engaged when I flip off the dash switch.  The last
time this happened, it was the relay, but this time a new one ain't fixing
the problem.  I think the part mentioned above is key to how the relay
latches, but haven't quite got it scoped out yet.
 
Thanks,
 
Steve Byers
HBJ8L/36666
BJ8 Registry
Havelock, NC