Power steering locks up

[indian_richard]

(09-22-2017 )Waterloo Wrote:  Steering box, steering wheel shaft u-joint or the pump. I went through this on my ProStar, I replaced the steering shaft as it was getting up there, that helped. Then it was getting worse, to the point of locking up, I replaced the pump, problem went away. If it is locking up like you state, I would lean towards the steering gear box, especially if it just suddenly started doing this without warning. If gradually getting worse, and then locking up I would look at the shaft and or pump.

When was the last time you flushed the power steering system and replaced the filter? I guess that would be my first attempt to fix, as it is the least expensive of the above.

I haven't ever flushed the power steering fluid. The truck has done this for a while now and it hasn't gotten worse over time yet.