I just did a PS flush on my '92... I sucked the reservoir empty first, then disconnected the return line to the reservoir. I slipped a length of 5/8" garden hose over the end of the return line (good friction fit) and ran it into a 1-gallon milk jug. I put a short piece of 3/8 hose on the reservoir and clamped it shut (where the return would normally go). Then I added about a quart of fresh ATF (Mobil 1 in this case) and started the engine. I moved the steering wheel back and forth from center, and added more fluid as fluid was expelled from the hose. Eventually I went thru 2 quarts of ATF using this method.