My 79 has what I believe is the stock steering pump. Car turned just fine with the original 15's and bf goodwrench tires and any speed, slow or fast. I added the 17 inch TTII's since I had an extra set with 245 toyo T1-S's in front and 255's in the back, now if I try and turn the tires under 2-3 mph. Like at a stop light when getting ready to turn right, I can't, or rather it's so hard to do I'm afrain I'll break something. And it's sound like some real bad resonance coming from the pump itself. It's like trying to turn my manual steering fiat at a stop, only with all kinds of noise.

I'm not ready to buy a steeroids system yet if that would even be a fix.

Any suggestions?


[Modified by munday, 2:37 PM 8/3/2003]

 

It sounds as if you just ran out of sufficient pump pressure to turn your front wheels when you changed to the bigger tires. However, with the car rolling at 2 or 3 mph you really shouldn't require anything close to the maximum pump relief pressure (even with your new tires). Maximum pressure would be required with the car stopped and the steering near full lock turn! Do you remember if your power steering with the original tires would reach full lock turn with the vehicle stopped?

The maximum pressure that your pump can develop is controlled by a pressure relief screw on the back side of the flow control plunger. The plunger is inside the power steering pump.

The following procedure can be used to increase the maximum pressure that your power steering pump can produce.

If you remove the power steering hose from the back of the pump, you will note that the hose nut screws into a fitting. The fitting has a one inch hex and can also be screwed out of the back of the pump. Just behind the fitting (and sliding inside the pump) is the flow control plunger which has a spring behind it which is pushing the plunger back toward you.

Unfortunately, the power steering hoses that are used on C2/C3 Corvettes are designed for 1100 psi maximum pressure. This is also the maximum pressure that the pump is set for.

If you remove the flow control plunger you will find a small hex head screw on the end that was furthest inside the pump. You should see some shims under the head of the screw. You might try unscrewing it and removing one shim. One shim should raise the pump relief pressure by 100 to 200 psi. Hold the plunger in a vise between two pieces of wood when you remove the screw. The outside diameter of the plunger must not be damaged or scored.

When you remove the small hex head screw you will find a ball, a guide pin, and a spring inside the plunger in that order. Make sure you reinstall them the same as you found them.

I wouldn't recommend going much higher than removing the one shim since you do not want to increase the pressure setting by too much. I am concerned that your power steering hoses may start developing leaks where you hose rubber is crimped to the metal end fittings.