I've done some searching and couldn't come to terms on a proper diagnosis so I'll just describe my problem.

My father took his truck out the other morning(-10 F), drove a kilometer, left it running and came back after 10 minutes. In that time, he lost his steering and brakes. No visible leaks or puddles. The oil in the pump is light brown looking but is within specs on the dipstick. Everyone on here says put in synthetic but it seems like a light switch, one minute it's fine, the next it's not. What things should I actually test to narrow things down?

Mike

 

Possibly a vaccum leak, as the vaccum pump supplements the power for the brakes and the steering.

 

I'm gonna hazard a guess and say the shaft between the vacuum pump and steering pump is broken in some way. with the engine running, remove the cap on the steering reservoir and see if the fluid is moving at all. If not, crack the pressure line on the back of the steering pump and see if fluid comes out. If not, the pump is not pumping for some reason. It's a pretty common problem. I would check out fixinrams.com and call Peter Gould. If something is broken down there, he would be the guy to call and get parts from.