Cooper-your dozer seems to be working well now and the operator is also improving.
Watching the videos I thought -if there were bulldozers millions of years ago, that's what it would have looked like with dinosaurs walking around them.
I know the problems you are having with the brazing. I brazed my Marion shovel together and it worked good on small pcs. but the more metal added just turned everything into a heat sink and I could not get the metal hot enough. Some of your joints to me looked like they were not hot enough to flow the silver. Some of this stuff might be worth a try-
http://muggyweld.com/all-products/coolblue Watch the videos and yes I know they are trying to sell the stuff but it looks pretty good. I didn't find this until after I finished my model. Oh well!