GM-GMC: Power Steering, steering gearbox, citrus heights ca

Question
I just recently purchased a 1989 GMC Suburban R2500 from an auction.  It needed a little TLC, but I have been able to get it back up and running.  One of my adventures, was to replace the steering gearbox.  This took a little time, but I finally got it comepleted.  I figured, while I was at it, I should replace the pump and hoses as well.  So I did.  I am proud to say...  there are no leaks :-)  However, occasionally when the engine gets at or around operating temp, the power steering goes out.  The fluid level is fine, and I bleed the system according to the instructions in the manual.  It steers like a champ when I first start it up.

Any suggestions?

Mike Thompson
mikeandmelthompson@gmail.com
Citrus Heights, CA
1989 GMC Suburban R2500, 454ci

Answer
Mike,

Congratulations on your repair effort!  It is not easy to repalce all the parts that you changed and not have leaks.

I gave your problem considerable thought and I also went through my 1984 shop manual.

Given the symptoms you have described, it is more likely that the pump is bad than the steering gear box (though either part could be causing the problem).

You should have a warranty on both parts, as most are factory rebuilt parts.  I would proceed by removing the pump and installing another one.

Occasionally, a rebuilt part does not work properly when it is installed.  Quality control does not always detect these kinds of problems after the rebuilding process is completed.

There is a pressure test, but the gauge is expensive to buy and probably not available for rent.  Testing of the power steering system should only be done by those familiar with pressure tests that can exceed 1,500 psi.