David,
you may check the ERA Cobra web-site to better identify the parts you are talking about.
I am using the same axle as you, though do not know what you mean.
Maybe it's the Watts linkage used on later CC Cobras.
start here:
http://www.erareplicas.com/427/rsusp.htm
Bob from ERA is not at the PC yet, so I (the servant)
jump in.
No bolt is supposed to rip off and beeing replaced from time to time!
Good luck,
Dominik