'82 Chev C20 Power Steering

Hello,

New to the forum, long time car nut, frustrating problem.

I replaced the PS gearbox, pump, and hoses on my '82 Chev. C20 over two years ago.  Although the system worked perfectly, it had a serious leak at the gearbox seal since I installed it.

Jump ahead to a few weeks ago.  I finally was able to work this issue (don't ask why it took so long, but the gearbox had a lifetime warranty).  I relaced everything again.  I mean new (rebuilt) gearbox, pump, hoses, filter, belt.  I did not want to take any chances.  Now I have absolutely no leaks.  Not a drop.  The system functions normally if you are rolling.  At a complete stop, there is essentially no power assist.  The idle speed is set to spec.  The belts are not slipping.  The fluid is full.  The system is fully bled.

If you rev up the engine at a stop, the power assist comes back.  Also at first start-up, when cold, there is power assist at idle and a stand still.  As the fluid warms to operating temp, you must rev the engine to get power assist at stop.

So here's my question:  

From the factory GM manual, it appears this could be either too much clearance in the gearbox or in the pump.  Apparantly, the only way to determine if this is the pump or the gearbox is to do a pressure test with gauges.

Based on my symptoms, I tend to think it is the pump.

Anyone have an idea as to which it is?

Thanks.

DAP

[discretesignals]

I have run into a few reman pumps where there was differences in either the pressure regulator valve or spring.  Usually, I take the old spring and valve out and use it in the reman pump if I run into a problem such as yours.  You may have already cored the old pump, so you may have to try a different pump.