OK, as I have posted before in other threads, there is a spool valve in the power steering unit that is held centered by a torsion rod/spring. Which is hooked between the input shaft and the output shaft.
I am oversimplifying and glossing over a few points.
When you try to turn the wheels, the torsion spring tries to turn the output shaft. If there were no load on it, it would turn and the power boost would never kick in.
But, when the output shaft does not turn, the spring twists and that causes the valve to open and supply the boost.
The amount of feedback you feel in the wheel is the spring tension. You can get different strength springs.
But, when you put in a lighter spring, or the one you have breaks, the steering becomes like a video game. Effortless steering. You have no feedback at all. When you turn the wheel, all you feel is the friction of the bearings.
But, even then, it still responds at the same rate.
In your case, something has caused the spool valve to become hypersensitive. Its supposed to open gradually as you turn the wheel.
Sounds to me like it is opening way too much.
At this point, I run head on into a sudden lack of knowledge. So its going to be assumptions from here on out.
I do not know if the spool valve in a ps unit is open or closed center. I had always assumed it was open center, but if it is, that presents a problem.
Again I assume, K20 correct me if I'm wrong, that the pressure line for the brake booster comes off the pump between the pump and the power steering unit.
If so, then the ps unit must be closed center. An open center unit would just let the fluid flow out of the high side, through the valve, and back to the pump.
When the valve is centered, there would be no pressure on the pressure line for the booster.
I suspect that either they make two different ps units one for hydraulic booster and one for vacuum booster, or, most likely something has come apart in the unit.
The best way to tell, would be to measure the ps pump pressure at the connection to the booster. But, unless it has one of those pipes with the pressure switch threaded into it that you could remove and hook up a gauge, it would be a lot of trouble.
ATTEN! I think I just found out what is wrong with the brakes!
I can't post a direct link, but here is how to find it.
Go here.
http://www.rockauto.com/
Drill down to Chev., 1982, G30 van, brakes, and booster.
Read the listings for the boosters. They show several hydraulic boosters, and they list different length rods for them.
One is 61mm, and another is 66.5mm. Bet thats the one that is giving you problems.
Also, check out the master cylinders. There are a LOT of different ones. You may still have the wrong one.
At this point, I am not sure which way I would recommend you jump. If the pedal pushrod is wrong, it might be causing the booster to be continuously activated slightly, draining off pressure from the pump causing the steering problem.
Letting the valve open farther then it should before the assist kicks in.
But, a bad steering unit might be killing the pressure to the booster causing the hard pedal.
Rockauto mentions brake codes on the Service Parts Identification" sticker. If you can find that, it might help determine which parts are supposed to be on that vehicle.
Hope some of that helps.
