Steering Aisin Part Number 5C3041 ?

There is an intermediate steering part that interfaces with the brakes in my 1995 4Runner (presumably in all 1995 4Runners). It is mounted near the front of the engine compartment on the top of the passenger frame rail and hydraulically speaking, is between the power steering pump and the steering box. Two brake lines exit from the back of this unit.I have no idea what it is and can not find reference to it anywhere on line. There is a label on the front of it, Aisin 5C3041. One friend indicated that it helps boost brake pressure, but again, I can find NO REFERENCE TO IT ANYWHERE!! I am sure some of you know exactly what it is and does; input? Thank you