Power stering fluid drops too fast.

On a 1994 lexus ls 400 power stering fluid drops every day I have fill up, I see a drop once in a while from the mittle of a power stering boot, I dont see drops on the floor, every morning I see smoke come out of the tail pipe for about a 15 secons and sometimes during the day. L dont know were my problem is please help thanks. If I had to replace the rack and pinion how hard is it to replace? Thank you.