If you know what you're doing:

and you are careful. You can take a power steering pressure measurement at
maximum turn to lock, that's to one side. Do it at both sides.

Remove the pump, and look in the service manual at the check valve, look
carefully because you get only one or two chances to do this, and why do it
twice.

Remove the check valve, and stretch the spring about an eighth or a quarter
of an inch. That will increase the pressure by a few hundred pounds. If you
get happy and stretch it to a half inch longer, look forward to replacing
steering box seals and hoses a few times a week.

Make sure you get a good manual!

Refinish King

Just a suggestion.  Try takin your foot off the brake next time it "stalls"
the p/s.  With offset wheels and such, the tire must turn when you steer.
With the foot on the brake, it is very difficult for the wheel to turn.