"Grinding" noise when pressing brake pedal and steering full lock

Hello and welcome to 2CarPros. The noise you are hearing is most likely the power steering pump. It provides both the steering assist as well as the brake assist on that van. If they are low on fluid or it is old and worn the pump will groan under higher pressures. The first thing to check would be the power steering fluid level and color. Old warn fluid can cause parts to make noises. The next thing would be to flush the old fluid out and replace it with new. If you still have the noise then a replacement pump would be the next step. Both flushing the fluid and replacing the pump will require the system to be bled of any air. This is actually one of the few times I recommend having a shop do a power flush as it gets more of the old fluid out than if you do it manually. Plus if the noise is still there after the flush, you already have new fluid in the system.

Please keep us informed of what you find.