New to the forum, fairly new to diesels, new to turbos, but fairly knowledgable about cars in general.

I just purchased a '97 burb K2500 diesel.

I noticed my steering assist drops away at slow speeds, like turning into a driveway. Looking under the hood, I noticed that the normal GM power brake assist is missing, and in it's place some type of assist unit that is driven by the power steering pump. Level of fluid in PS pump is normal and is a nice red color.

I'm wondering why there is not a normal power brake assist unit. I'm guessing because the turbo would have ill effects on the amount of manifold vacuum available, or is it somehow related to it being a diesel?

It doesn't seem normal to have to sacrifice steering assist when brakes are asking for assist at the same time. Is this a common problem and what is the cure?

Thanks

Mark in MA