power steering fluid change

Power steering has a circulation to it like cooling system. That is about all you get unless you drain the rack but that's huge work. I just suck out the reservoir before the fluid goes bad and just replace. I use a more frequent interval like I do with cooling system so my systems never go bad. This way I don't have to get anal on how much old fluid I get out. So I also don't drain my block when I do cooling system. Some people think otherwise. If I had a really bad system or a car I just bought and do not know history then I'll go the extra mile the 1st time then go back to my regularly scheduled program.

For ease sometimes I'll change the fluid a 2nd time and dilute out residual fluid. IMO the key is don't let fluid get nasty in the 1st place.

40nm is 29ft-lbs. That does not sound like too much but I never use a torque wrench except on critical fasteners, heads, con rods. I bet it took more than 29 to get it off.