After blowing bearings out of a hub last weekend, I replaced one entire hub assembly and installed new bearings and brake pads on all the other hubs on my tandem trailer. I know many have had the frustration of the plastic Vortex hub / grease caps cracking. You can get the plastic replacement caps that have supposedly been upgraded or, as in my case, I called my local Bass Pro Shops (Concord, NC) and asked if they had the aluminum replacement caps. They had just gotten a batch of them in stock and I went by there this morning and picked up four of them. At only $7 each (cheaper than the plastic ones) they’re a great replacement / upgrade. Just wanted to pass this on to those interested.