Short power steering loss then normal again

Today on my way home from work I started up my Cherokee after it had sat all day and I made a left and then another quick left to leave the parking lot, when I went to pull the wheel back to the right there was no power steering until I muscled it arround a bit then it was fine again.

It's happened before when when it's cold or when it sits for long periods of time. Usually when it happens there's no power steering until I move the wheel after I start the Jeep but today I had it, lost it then had it again.

It's a 90 XJ 4.0 AX-15 and about 190k

What causes this kind of problem?

Belt?....old, glazed, insufficiently tensioned.

Stuck valve.

old_man said:

Stuck valve.

Click to expand...

How could I go about getting this valve not to stick?

Lou-The belt's new

That's ODD, my PS doesn't work unless it's cold. Now thats' wierd. The only other way to get it to work is w/ increasing the RPM's. At idle it doesn't work (accept in the cold of winter).

PS pump bad? Fluid level is fine.

My 87 used to do that when the belt wasn't fiddle-string tight. It never made noise, so it wasn't that obvious what the problem was. I got a tension gauge and that ended the problem.