Hi Shaun
Not my idea, I saw it in someone's video, and thought it was pretty slick. I used Dupro threaded couplers that I had, and some 4-40 rods. The 4-40 rod just bottoms out in the coupler, essentially making it a "push" rod. It floats during retract/extension cycle.
Can do the same thing by cutting any size control rod, slipping a piece of tubing over one half and soldering (or gluing). The other half is free to slide in and out of the tube. I am going to replace these couplers as I would like the female side to be deeper. It is possible that the floating rod can come out if you apply rudder during the extension cycle. I set my plane up so steering is neutral/inactive with gear up, which happens as soon as you hit the switch.
On the extend cycle, if you had heavy rudder (for whatever reason) and select the gear down, steering servo will drive, and one of the floating rods could come out of the coupler as the gear swings. Unlikely in flight, but it did happen on the bench, and that's enough for me.
http://www3.towerhobbies.com/cgi-bin...?&I=LXD924&P=7