1989 Honda Prelude power steering leak and foaming issue

1989 Honda Prelude mileage: 95,000. I have had the steering rack replaced three times by the same mechanic and I am still having the same problem. There is power steering fluid on top of the reservoir and even on the underside of the hood above the reservoir. The fluid seems to leak sometimes and other times it does not. The fluid also appears to be foaming up in the reservoir. The mechanic that I took it to is trying to help me and has only charged me once but this has been going on for too long and I cannot afford to take it to a dealer and pay again. What do you suggest?