I have a 1995 Ford F150 pickup.I need to find a diagram on how the hubs
assemble.I also need to know if one of the hubs are broke if it will keep the other wheel from engaging?

 

I cannot help you with a diagram , try a Haynes or Chilton manual for that, even from a library. As for the engaging problem the answer is yes. Both hubs have to be locked in otherwise there is no transmition of power to the wheels. When I bought my 93 I found I had a problem with the hubs the first time it snowed. I turned both hubs in and put the truck into 4wd and promptly got stuck.We get LOTS of snow! Anyway, I managed to get the truck unstuck and home. I crawled under neath with the transfer case in 2wd and turned the front drive shaft and found that it turned even with the hubs locked in. I then reached in the steering knuckles to turn the individual universal joints to see which side was not locked in. After I found the offending side I jacked up the truck to pull the wheel (not required) so I could pull the hub off. When I reefed on the wheel I found that there was play in the wheel. At first I thought it was the steering ball joints but found they were OK. When I pulled the hub off I found that the axle bearings were loose, to the point that the hub was in a bind when the wheel was on the ground and could not engage. All I had to do was tighten up the bearing lock nut and all was well again. I hope this is of some good for you.