Noise from steering wheel of a Toyota!


#1

Hi,



We have a 2000 Toyotal corolla CE with 100,000 miles on it. Its been a great car so far and we have been good with doing all the regular maintainance on it. Very recently, we started to notice a noise coming from the steering wheel. We think that its is from the steering wheel or components connected with it because by rotating the wheel we can have it go away for couple of minutes but it comes back soon. This noise is most noticeable when teh car is on and not moving. When we drive fast we don’t hear it.



We took it to a couple of mechanics and they had a few different suggestions. One guy said we will have to change the steering wheel pump (which is very expensive), the other guy said we should flush out the steering wheel fluid and the third mechanic said flushing out the steering wheel fluid is not a great idea as it might corrode the other components so we should get some tensioner attached to the steering wheel checked.



With so many different opinions we are really confused !!

I would really appreciate any suggestions from you guys out there. Thanks a lot !!!


#2

I beleive what you’re discribing is power steering pump whine. This happens when the power steering fluid becomes contaminated from oxidation, or if the power steering pump becomes worn out.

Think of a hub with slots in it. In these slots are metal blades that move up and down in these slots. Now position this hub and blade assembly ecsentrically inside a bore or off center to the bore. Where the hub/blade assembly sits closest to the wall of the bore is where the blades must move up into their slots. All the other blades are sticking out of their slots. Now start rotating this hub/blade assembly inside the bore. Each time a blade comes around to where it’s closest to the wall, it must move up its slot. Once it passes by this area the blade must move down it’s slot. If any of the blades fail to completely come out of it’s slot, a gap results when that blade comes around to where it’s closest wall of the bore. This gap then allows the power steering fluid under pressure to bypass between the blade and the wall of the bore. This causes the blade to vibrate like a reed, and this is what causes this noise.

Changing the power steering fluid sometimes will free up these sticking blades so the noise disappears. But if the pump is worn at the bore, changing the fluid won’t help. The pump requires replacement.

What determines when noise ocurrs and when it doesn’t is when the demand for power steering assist is required. If the car isn’t moving, and the steering wheel is turned, the demand for power assist is at its greatest. So the pressure is higher in the power steering pump. The higher the pressure, the more likely the blades will vibrate. When the car is moving, it requires less power assist to turn the wheels, so the pressure is lower and it’s less likely the blades will vibrate.

So, first flush the power steering system and see if this stops the noise. If not, then power steering pump requires replacement.

Tester


#3

Thanks, Tester, for an informative description of the power steering system. I also have a Toyota Corolla with a related problem, though this one is a 1996 model with only 40,000 miles. Just purchased it as a used car, and brought it to the shop asking them to give it an inspection. I figured belts and hoses, etc might be dry and cracked, plus I heard a sound that suggested a power steering belt might be involved. As you described, while the car is parked and the wheel is turned, it makes the most noise. But the noise is enhanced a bit when I step on the accelerator though driving straight.

The shop said the ps belt was indeed loose, but that they also found a leak in the ps pump. They quoted me a price of about $800 to replace the pump and belt, parts and labor included. Seems a bit pricey, or is that average? In the interest of saving my valuable time, I’m inclined to get the whole thing repaired. But I’m wondering if there’s a way I can easily inspect the pump to confirm there is really a leak. Does anyone have comments or suggestions?

Mahalo from Kailua