I would just fill the bore with grease and give the outside a coat of grease and call it good. Stick them in a 5 or 6 inch PVC pipe and seal the end caps with silicone.
http://www.oreillyauto.com/site/c/d....oap?ck=Search_N2421_-1_-1&pt=N2421&ppt=C0139
Crap. Now there will be a run on PVC pipe.