Power Steering Boost

[campbelljj]

My 91 Q seems to have lost some power steering boost. In other words the wheel is hard to turn at slow speeds. At higher speeds, say 25mph+ it feels great. My independent mechanic says he can't diagnose because the system is proprietary (he tried). The pump is clean and quiet, the fluid is topped off, no signs of leakage anywhere on the rack, etc. This just occurred and I am not sure if I have to go to the dealer or if there is a simple fix?

[Q45tech]

Proprietary just means he does not understand it nor has the FSM nor wants to spend the time diagnosing!

Either the speed translation to pressure module or the pressure solenoid or wiring between the two.

Since you didn't mention speedometer problems or engine check light illumination.

Fairly common situation so I would be suspect of using your regular guy FOR ANYTHING if he cannot deal with this simple problem!

[ScottJackson]

I'm with him. The pressure solenoid is down on the steering rack itself and two bolts hold it on along with 2 wires that are plugged into a harness. You can hook up 12V to the pins in the wiring harness with little jumper wires and if it clicks, it's probably fine. Is the power steering by chance working fine when it's cold but sometimes after it's been running a few minutes it gets very hard to turn like the power assist just shuts off? Mine did that and I did a lot of digging until I finally found that the spring loaded pressure regulating plunger inside the steering pump was sticking at times and bleeding off all the pressure. The fix was to pull off one steering line from the pump, start the motor for a split second (shoots fluid out along with the little plunger and spring), then lightly sand the edges of the plunger so they wouldn't catch the bore it goes in, and then put it back together. As for the pressure module, it's in the dash just to the right of the steering column and what normally happens when that fails is the steering assist will cut out and come back in at random when you hit bumps. Firmly smacking the dash with your hand will produce similar results. What happens is the solder points on the circuit board inside the module crack and lose connection.