1993 power steering pump leaks at the alluminum hose where the O-ring is new pump

You can replace the very pricey O-ring (see item #4 below), but it's possible that the soft aluminum hose connector is damaged. This is a high pressure connection and it needs to be perfectly seated. You might be able to 'dress' up the connector and apply some sealant to the end before tightening it back up, but it's a long shot. If the hose is badly damaged, you'll have to replace it. It's not an easy job. Getting the hose off the back of the pump is the easy part. You'll have to remove the power brake vacuum booster and master cylinder to get access to the hose end at the steering rack connection, and more than likely you'll have to loosen the engine mount to tip the engine forward as well. O-ring is about $65 each, part#26001594. You need one at each end of the hose.