[Grant]

Sounds like what happened to me last Sunday, pump shit itself and I had to use the Armstrong steering method (big biceps and feet to turn the wheel)
Also if you are running a power steering lubricant other than genuine article "Mopar"
you can have problems. Look up most lubricant manufacturers guides and they mostly state "See Daimler Chrysler"
the correct oil is clear and $13.00 a litre comparable to other power steering oils, if you are using auto trans fluid then you will end up with problems with the system, before pump shit itself I had similar problems to yours (used to use another supposedly compatible oil (Castrol)) cost me another pump (both bearings and front seal collapsed).