How do you figure that? He would have a light on the dash if there was an issue with the ABS/wheel speed sensor but would most likely still have brakes. Brakes generally don't fail from wheel faulty wheel speed sensors. But just for giggles - is there an ABS light on the dash?

That said, an '02 model year truck would probably only be RWAL. For that system, the speed sensor is on the rear diff.

Obviously the first thing to do is to verify the p.s. fluid level and make sure it's full. You said there was a noise on cold start sometimes? Could be the belt slipping/going away, that's a relatively cheap/easy fix. Maybe try that and see if that helps? Not likely though if it's an intermittent problem but obviously sometimes noises disappear when the truck warms up to operating temp. Same with the pump - if it was the pump or hoses, the problem would most likely be there all the time.

If not the belt, then it's probably the booster. Probably a good idea to replace the hoses if you change it.

Sorry couldn't be more help. Maybe Guitar Jones will chime in, he'll probably know more.