1997 tacoma steering problem

I have a 1997 tacoma with 275,000 miles on her. Have had little trouble. A couple of seals, a set of brake pads, and a cheap set of plug wires that shorted out( my fault, should have got better quality). About a year ago, I started getting a little shimmy in the wheel going down the interstate but it was only at high speed. I figured I needed a line up.The power steering pump started making a noise about a month later. I kept driving it till I started having a bad smell and the steering wheel got hard to turn, on tight turns. I priced an OEM pump and a rebuilt at Advance auto. I got the one at advance for 90.00 after a 50.00 coupon, as the OEM was over 400.00. I installed the pump and bled it by turning the wheel slowly each way, as I was told. The pump stil made a noise and the steering wheel was hard to turn on slow idle. I took it back and got another one. The second one is harder to turn at slow idle. I can bleed it and the pump gets quiet and drives OK. I drove it 50 miles and the wheel had a little shimmy at 55-60 for a while but went away. When I got home the pump was making a noise again. I bled it and the noise went away but it's hard to turn the steering wheel at idle. I have check the rack and don't see any leaks or problems. Got an inspection about a week ago and they found no problems with the ball joints or tie rods. Do I get another pump or do I have a problem in the rack. Any help would be appreciated. Don

 

WOW, I thought someone would have had this problem or at least an idea. Don