Maybe I'm just lucky, but I've never had any trouble with landing gear. It's usually the last part I attach during a build (prior to rigging), after getting the upper wing in place. If I'm working on a monoplane, I'll set the model on top of some paint bottles so I don't crush any of the cockpit or fuselage. I place the model upside down and attach the main landing gear struts, usually with Testor's tube glue. This gives me a little time to fiddle the axle in place. Wheels always go on last. Since I hang all my models from the ceiling, I just glue them on the ends of the axle.
I hope this helps,
Brian da Basher
(currently bashing a Curtiss H-16 in 1/144)