Mechanics

SLIGHT LOSS OF POWER STEERING

2005 Toyota Sienna • 6 cylinder FWD Automatic • 105,000 miles

2005 Toyota Sienna CE, 105k, New England Area.I owned this van for about 3 years, with no problems. As I pull out of my driveway, I suddenly noticed my power steering felt a little tough, as I made my turn with no noise or buzzing. Since then, turning left/right sure dont feel as smooth as before. I checked my Power Steering Fluid which was clear/clean and noticed no pieces of metal, no lost of fluid, or any visible leaks. The vechicle still turns, but it feels like its turning with half the effort. When turning, the steering wheel doesn't straighten itself out, when releasing the steering wheel. I read that the steering rack's knuckle could be rusted, and that replacing the pump wont fix it. Others still say its my power steering pump. So I took it to Toyota, who tell me the pump is fine, and suggested a power steering flush. I dont know what else to try. Any Suggestions? Thanks in Advance!
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Spooky1469@live.com
March 13, 2011.




Tight ball joints are a possibility but not very common. A binding upper strut mount will cause hard steering and poor return as you described, but normally that is accompanied by a popping or banging sound as you turn when the bound up spring breaks free and rotates. If the pump output was weak the power assist would improve when you raised engine speed a little. That won't cause a returnability problem. To check for a tight ball joint or upper strut mount the steering linkage must be disconnected at the outer tie rod ends, then the turning force must be measured unless the tightness is real obvious.
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Caradiodoc
Mar 13, 2011.
Thank You for responding to my first question.I did a power steering flush and it seems to work so far for 3 months.

About two weeks ago, I was making a right-hand turn, and heard a single spring-like sound coming from somewhere near my front wheels or underneath between my front wheels. It was best described as. "DONG" "DONG". It was a sinlge "DONG" at frist, but it been progressing. It doesnt happen all the time, but I noticed that it tends to act up when driveing around a parking lot or parking. And also not so much when car is warm.

I dont know if it even related to my previous steering issue. I hope you can shead some light.

That suggests a binding upper strut mount. They make more noise at lower speeds. At higher speeds it is harder to hear and the vibration from bumpy roads lets them release and turn easier. Also, at higher speeds you aren't turning as far.

To identify a binding mount, reach over the top of the front tire and put your fingertips on one of the upper coils of the coil spring, then have a helper slowly turn the steering wheel. Some roughness is normal but the spring should rotate freely with the wheel. If it is binding, you will feel the spring wind up then suddenly break free and turn with a snapping sound.

Binding mounts are not serious in themselves but they can prevent the steering wheel from centering itself after you make a turn. That can make a vehicle irritating to drive.

Caradiodoc
Jun 7, 2011.
Hello,

Thank You for the insight, I will report my findings when I explore your great suggestion.


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