Truck won't turn left

[Wiseman]

You won't be able to duplicate the problem in the shop . This thing happens only when the power steering fluid get overheated. Ones cool down little bit everything goes back to normal . The only solution I know of is installing an suitable cooler on the return line .
I guess it all comes to component tolerance in the steering box distributor and having hard time functioning when oil gets overheated slightly above so called normal operating temperatures.