I posted about my problem but got no replies here:
http://dieselplace.com/forum/showthread.php?t=36596

I've since gone to the dealer and they have ordered a new hydroboost. Meanwhile, they say I can drive my truck, but I won't because I don't feel I can trust it. Yesterday I moved it around at the property and I notice then when I turn sharply the brakes come on. This isn't reassuring at all. Needless to say, I'm missing my truck already and the family boat is staying parked in the barn, etc.

The "leak" that I hear whenever I turn the steering wheel -- what is that? Is it any way related to the fact that my steering column is loose enough that I can move the steering wheel side to side and actually feel play? The female service writer says she thought that was just an adjustment in the tilt wheel mechanism. The stealer did replace the steering shaft for the horrible rattle which got to the point that I could hear it at any speed over any bump. I don't know what part they used, but right now the rattle is gone.

Could anyone explain this hydroboost system to me and tell me how turning the wheel could put the brakes on? I really don't have much confidence in the local stealer but they are the closest and they seem friendly enough. The more I know, the better.

Thanks.

On a gas engine, you have vacuum available to operate accessories, this includes the brakes, hence vacuum boost. Since a diesel does not produce vacuum, you need another source of energy to run things, again like the brakes. The source is the hydraulic fluid from the power steering unit. The hydroboost system just uses hydraulic pressure to give you power brakes. As to turning the wheel and having the brakes be applied, I don’t have any idea.

When you turn sharp the fluid pressure in the system jumps up to around 2500 or so PSI. Doing so may bypass pressurized fluid through a seal or piston inside and apply the brakes.

All you are doing when you apply the brakes is to open a valve inside booster so press. fluid can act against piston, this gives you power brakes. It's been awhile since I've been inside one since it's usually more cost(and time) effective than rebuilding. Usually there are scuffs or burrs in piston bore and these cause leaks.

No sooner did I post and my internet service pooped out. Just got back online now.
Thanks for the replies. The truck is at the shop now, and I'll let you all know if their repair actually fixed it or not.
What I just didn't understand is the hissing sound which to me sounded like a vacuum leak whenever I put any pressure on the steering wheel.
Seeing as how the stealer has had the truck since yesterday already, I'm wondering if they ran into more issues than they originally bargained for. They had all the parts when I dropped off the truck yesterday.
Jim

I got the truck back, hydroboost was replaced and the symptoms are gone.
Now I have a new issue: The accelerator pedal vibrates, or buzzes, under light acceleration or pressure. This is new since the stealer had it. Anybody have a clue what causes this? Would the mechanics have had to remove the accelerator while repairing the hydroboost??
It is petty, but irritating, like a buzz in the sole of my shoe when I am lightly cruising. Yes, I know. Floor it and quit complaining...
Guess I'll go back to the stealer again.