i am in the process of replacing all the original hoses on my 77 bj40. while changing the vacum hoses i noticed that that PO had removed the carbon filter and just connected the two hoses together. this is my first diesel so i am still learning ? is this going to be a problem in the future? i also found a lone hose coming off of the gas tank that used to be a vent system? it goes through the floor pan and there is a connection piece but no hose connected to it? nothing but rust on the end of it so i'm guessing it hasn't been hooked to anything for some time. was this a return hose at some time? any help would be greatly appreciated...