<VV> Problems on the road returning from Ventura

[shortle]

I put 1900 miles this last week on my Rampside with only 1 breakdown. My fan bearing seemed to "creap up" until the fan was scraping on the bottom of the top shroud (breaking the mag fan fins of course).In Williams Az.(350 miles from home) it finally snapped the fan belt. I was able to hammer it  a couple of times back down which allowed me to get back home. The worst part for me is I purchased the "ultimate" top cover w/ bearing already installed about 2 years/6,000 miles ago so I  was quite surprised when this happened. My first question is why did this happen? What can be done in the future to keep this from happening? Am I better off using a good original fan bearing in the housing that hasn't been changed (I still have a couple)? 
By the way, we had a great time in Ventura and the Rampside did great except for this.
Timothy Shortle in Durango Colorado