My 97 T&C has been having power steering issues for the last six months or so. One day the power steering stopped working without warning. The next day it worked like new. Then I'd have a few days that it only had power steering turning in one direction but not the other.

It stopped completely for about three months and came back on about a month ago. Now it works and doesn't work mutiple time during a drive.

It doesn't change sound or feel when it turns on and off. There is no indication of it working or not that I've been able to notice.

This doesn't strike me as a normal type of failure, but I could be wrong. I'm going to replace the pump first, and then the rack if the pump doesn't fix it. But I'm just curious to know what would cause this type of failure. Maybe debris in the system? I have sucked some nasty looking stuff out of the system.

 

Maybe the crap in the system is causing the vanes in the pump to stick or screwing with the pressure valve.