Power Steering Rack Failure?

[tony303]

Hi all,

Driving home from the mountains yesterday on I-70 lost power steering in 2003 4Runner V8. Fluid level is fine. I can barely turn when braking or stopped. When accelerating I can turn with relative ease. Went to mechanic today and:

- No leaks.
- Pump is pumping.
- Revving engine does not help.
- No noises, grinding, squeals, etc.

They said I needed a rack replacement. Most of the symptoms for rack replacement seem to be leaks, loose steering or grinding. Does anyone know of a case where the rack fails with tight steering symptoms but no leaks.

Note: someone put the blue fluid in instead of the ATF which everyone recommends, but my mechanic felt that wouldn't cause this problem.

Thanks!

Tony

 

[chitown40]

I don't have a real clear cut answer for you, but let me ask this...

Was your fluid reservoir low enough where you may have been on a steep enough grade to cause the pump to suck in a little air?

If so, put the front of the truck on jack stands and while running turn from lock to lock a few times and look for any air bubbles in the reservoir. Keep turning the wheels until there aren't any bubbles. If you still have the issue I'd start looking at the rack more closely and even double check that the pump is pumping adequately.

 

[tony303]

Thanks for the tip! The reservoir was full - right at max warm level. The mechanic ran the engine with the cap of the reservoir off and looked in with a flashlight and saw that the fluid was moving from the pump. They revved the engine and tried to turn the steering wheel in place and no change.

 

[nevada]

Hi all,

Driving home from the mountains yesterday on I-70 lost power steering in 2003 4Runner V8. Fluid level is fine. I can barely turn when braking or stopped. When accelerating I can turn with relative ease. Went to mechanic today and:

- No leaks.
- Pump is pumping.
- Revving engine does not help.
- No noises, grinding, squeals, etc.

They said I needed a rack replacement. Most of the symptoms for rack replacement seem to be leaks, loose steering or grinding. Does anyone know of a case where the rack fails with tight steering symptoms but no leaks.

Note: someone put the blue fluid in instead of the ATF which everyone recommends, but my mechanic felt that wouldn't cause this problem.

Thanks!

Tony

that's strange.
those 2 sentences contradict each other.

I have seen racks fail, without leaking.
IF the pump is working, theres really not much left that it can be. maybe an obstruction in the line?

 

[TOY2G]

Thanks for the tip! The reservoir was full - right at max warm level. The mechanic ran the engine with the cap of the reservoir off and looked in with a flashlight and saw that the fluid was moving from the pump. They revved the engine and tried to turn the steering wheel in place and no change.

There is a little screen (filter) on the pressure side line in the rack, it could get plugged. if increased RPM does not help but it steers better under acceleration, it is likely it is just easier because of the weight transfer to the rear of the vehicle during acceleration. the weight shifts off the front steering wheels to the back making them momentarily easier to turn.

 

[tony303]

There is a little screen (filter) on the pressure side line in the rack, it could get plugged. if increased RPM does not help but it steers better under acceleration, it is likely it is just easier because of the weight transfer to the rear of the vehicle during acceleration. the weight shifts off the front steering wheels to the back making them momentarily easier to turn.

That sounds about like what I am feeling when I drive it. Is it possible to unclog/replace the filter instead of replacing the rack?

 

[TOY2G]

That sounds about like what I am feeling when I drive it. Is it possible to unclog/replace the filter instead of replacing the rack?

It can be possible, I did it on my black one. I was working at a dealer at the time and i had them do a flush afterward. Now... mine was not blocked all the way like yours it was just getting where it was harder to turn standing still.

since i did not do the work, i do not know how he cleaned the screen, I suspect he just pulled the lines at the rack and cleaned them with some sort of brake cleaner. then hooked them back up and did the flush. once you undo the lines at the rack you may be able to clean it pretty easy.

Also worth mentioning...if the center seal goes bad in a rack you can get the same results as you are having

 

[BlackWorksInc]

The pump could also be weak, just because fluid moves in the reservoir doesn't mean the pump is producing enough pressure on the output side. I'm trying to figure out what it could be and how to properly diagnose it as the center seal could also cause a similar issue. Anyone ever done a pressure test on a P/S Pump before? (I don't remember if I was taught to do that to be honest)

 

[WhiteBoomer04]

So I have no mechanical proof of this, but when I was wheeling in the snow a year or so back, with my 37's I believe I cooked my oil because It turned black, it spit a little out under the cap and I basically lost power steering. It would surge in and out a little on the way home on the freeway.

A mechanic friend told me that it was probably the end seals leaking.

I replace the rack and installed a cooler inline. Don't seem to have any trouble now.


Just my experience.