Hi Guys from sunny england!
Have a 99 3.8 camaro, just fitted a set of are wheels, 18" dia 8.5 front 9.5 rears with pirelli 255/40 & 285/35s on the back. Also replaced all front and rear bushings with prothane kit, front and rear anti roll bars with eibachs.
This used to happen with the stock wheels but not as much.
at low speeds with a lot of lock a violent judder as though one tyre is skipping can be felt through the wheel....heads turn when it happens so it must sound odd from outside?
car has done 100k, tracking is spot on....is it the rack or the pump? just fitted new idler pulleys and tensioner system....could it be that?

all help much appreciated.
cheers ian

 

The normal process to check this out is to put a pressure gage inline on the high side pressure between the pump and the rack. If the pump is not outputting the defined pressure it is a pump issue. If the pump is outputting enough pressure then it is the rack. Low pressure from the pump and leaking seals in the rack will cause the same issue and both tend to be worse when it is cold out.

The rims themselves can cause the issue or as you are seeing or the rims can make a minor issue a lot worse. If you could look your car straight on and draw a line through the ball joints then to the ground that should be the center of the tire. This allows the tire to pivot around it center. When you install different wheels you risk making this off. As you can imagine rotating the wheel when the rotation point is not center of the tire greatly increases the amount of hydraulic pressure needed to turn the wheel. To read more about this just google SAI (Steering Axis inclination)

Edit: It has been my experance that power steering pumps make a whining noise cold as they drop pressure Racks leaking make no noise.

Cheers

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