power steering prob.

[94frdrngr]

I have a 1994 ranger 4x4 with the 4.0l and automatic transmission. Last week my power steering started acting up. When I turn a corner and let the steering wheel rotate back after turnig it doesn't. I have to turn it it back. I hope the way I am describing this makes sense. I checked the hoses , fluid level and everything appears to be good. Should I replce the pump and lines? Thanks for the help.