Coupler for an E-R HO sharknose

I am trying to replace the hornhook couplers on an E-R models HO Sharknose but can’t remove the hornhook - Is it held in by a screw or push pin? Any suggestions on how to remove the coupler short of breaking the shell would be appreciated

This is a push pin holding the coupler in place. Grab it with a pair on needle nose pliers. It a bit tight but it will come out. Heres a link to instructions for the conversion from Kadee using the #34 coupler set.

http://www.kadee.com/conv/hocc50.htm

Pushpin or screw you should be able to get it out. Now to replace it there are lots of options as long as the package says Kadee. I use #78 on all my Locos, they are protoypical in size and are completly assembled. You may need to modify the shell slightly for a proper fit but they look great