99 Noise/Steering Wheel Vibration Turning L or R

[dcgriswold]

My 99 Safari makes a buzzing, not a squeal, humming noise when I turn the wheel left or right while under power at any speed...such as in changing lanes. The turning movement, either right or left, does not have to be much. The sound is more noticeable turning to the right. You can also feel vibration in the steering wheel when making the turning motions.

The pump was replaced about a year ago...less than 25K. The noise just recently started. I believe the car has hydro boost.

Does this sound like the pump going out, or perhaps air entering the system through a hose or fitting? There are no leaks seen and the level is full.

The brakes work fine and the steering is smooth. The noise and vibration is annoying. Even if I turn up the stereo I can still feel the vibration.

Thanks for the help.

[Lumpy]

Does that only while rolling? Not while sitting still?

How about wheel alignment? Or do you feel like it's somewhere in the pump/gears?


Lump

[dcgriswold]

Hi Lump. I do not think alignment. The car goes straight down the road. I can take my hands off the wheel and the car does not veer. Also tire wear shows no signs of mis alignment.

The sound occurs when turning left or right...a buzzing that is also felt in the steering wheel.

It is more noticeable when rolling. There is a sound when stopped at idle, turning the wheel left or right, but that sound seems like normal ps sound. That sound is the same turning the wheel left or right when at idle. It is not a buzzing type noise I hear while rolling and the steering wheel does not vibrate.

[RECox286]

With out being right there to listen, it is difficult to say what the problem may be. Chevy describes several noises associated with steering pump problems,

Chirp, growl, groan, rattle, knock, swish, and whine. You have already mentioned that the system seems to be functioning as advertised, and the fluid level is OK.

There could be: excessive back pressure in the hoses, scored pressure plates, thrust plate or rotor, extreme wear of the cam ring, air in the oil, poor hose connection,

loose pump pulley nut, pump vanes sticking in rotor slots, pressure hose touching other parts of vehicle, and faulty flow control valve.

Perhaps you should take it back to the shop that did the replacement and see what they think.

Bob