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Discussion Starter #1
My younger brother 1995 corolla LE makes hissing / screeeeeeching sound while steering extreme right or extreme left otherwise it's ok in any intermidiate positions of steering wheel. It sounds like metal grinding. We changed worned power steering pump belt but still same.

Folks, any suggestion???
 

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Discussion Starter #3
I agree it may be pump,

But if it's pump then why no sound in intermediate positions, only while extreme right or extreme left when steering gets locked???
 

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operation boro thunder
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^because at the extreme left/right position the pump creates the greatest resistance. Try tightening the belt a little more. Hissing is normal. Thats the vacuum valve opening up to keep your engine from stalling.

BTW thats a cool sig :thumbup:
 

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Discussion Starter #5
project trueno
Try tightening the belt a little more. Hissing is normal. Thats the vacuum valve opening up to keep your engine from stalling.
I will try tightening up the belt. but, hissing is like screeeeeeeeeeeeeeeeeeching sounds like metal grinding. Which vacuum valve you are refering to, you mean VSV? DO YA SUSPECT FAULTY VACUUM VALVE?
 

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Discussion Starter #7
Bitter
could be air in the system? the air cavitating through the vanes of the pump can make some loud nasty sounds.
IS THERE ANYWAY WE CAN DRAIN POWER STEERING FLUID LIKE ENGINE OIL AND RE-FILL TO THE TOP AGAIN?
 

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operation boro thunder
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bonnie* said:
project trueno


I will try tightening up the belt. but, hissing is like screeeeeeeeeeeeeeeeeeching sounds like metal grinding. Which vacuum valve you are refering to, you mean VSV? DO YA SUSPECT FAULTY VACUUM VALVE?

So.....your hissing sounds like a screech? You just lost me there.:confused:

The vacuum valve is really just a plunger inside, with 2 nipples connecting to 2 vacuum lines, going to the throttlebody. Normally the plunger blocks the 2 passages (nipples) so air can't be bypassed. But when pump builds up pressure (such as turning your steering wheel) the hydraulic pressure pushes the plunger, allowing the 2 nipples to now connect. Your throttlebody then through the vacuum line connection, takes in more air to raise the RPM, preventing engine stall.

The VSV could be on the PS pump itself (AE86), or on the steering rack (AE92, and possibly the later FWD sedans as well)

Anyway, faulty vacuum valve would just cause your RPM to drop when you turn your steering wheel, so thats not your problem here.

Just try tightening the belt first.
 

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operation boro thunder
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Bitter said:
could be air in the system? the air cavitating through the vanes of the pump can make some loud nasty sounds.
If there is air, then you just have to bleed it.

With engine on (pump circulating fluid), you turn your steering wheel from lock to lock several times. Top up fluid. Repeat until the fluid level stops dropping.
 

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Discussion Starter #10
project trueno
The vacuum valve is really just a plunger inside, with 2 nipples connecting to 2 vacuum lines, going to the throttlebody. Normally the plunger blocks the 2 passages (nipples) so air can't be bypassed. But when pump builds up pressure (such as turning your steering wheel) the hydraulic pressure pushes the plunger, allowing the 2 nipples to now connect.
WHERE IS THAT F... FUNNY PLUNGER IS? YOU MEAN INSIDE POWER STEERING PUMP? CAN I REPLACE OR SERVICE PLUNGER?

BY THE WAY RPM DOES NOT DROP WHILE TURNING LEFT AND RIGHT IT DOES NOT SCREEECH WHILE TURNING LEFT AND RIGHT BUT SCREEEEEEEEEEECH WHILE MAKING A THREE POINT TURNS WHEN STEERING WHEEL IS LOCKED AT EXTREME RIGHT OR LEFT, SOMETIMES WHILE BACKING UP.

TOMORROW I WILL JUST TIGHTEN-UP POWER STEERING BELT AND SEE.
 

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Discussion Starter #12
Tomorrow More Feedback After Tightening Up Belt
 

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Discussion Starter #14
THANKS TO ALL OF YOU GUYS WHO RESPONDED THIS.....

We flushed the power-steering pump with miniature rotary pump with flexible tubing and proper fittings with almost 4-5 litres of fluid until the color matches with original one.
POSSIBLE AIR-CAVITATION NOISE HAS BEEN GONE AFTER FLUSHING & RE-TOPPING. THANX BITTER!!!

The steering performance is much much better than ever before.
THE BELT IS TIGHTEN-UP PROPERLY.
PROBLEM IS SOLVED.

SPECIAL THANKS TO UNCO & PROJRCT TRUENO WHO RESPONDED WITH THE INFORMATION REQUIRED.
 

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Powersteering fluid is very rarely flushed and replaced. Like brake fluid, it will absorb moisture over time. Also its additives will lose their ability to lubricate over time. I flushed my powersteering pump after noticing the fluid was a dark brown and had a very pungeant odor. You did exactly the right thing.


bonnie* said:
THANKS TO ALL OF YOU GUYS WHO RESPONDED THIS.....

We flushed the power-steering pump with miniature rotary pump with flexible tubing and proper fittings with almost 4-5 litres of fluid until the color matches with original one.
POSSIBLE AIR-CAVITATION NOISE HAS BEEN GONE AFTER FLUSHING & RE-TOPPING. THANX BITTER!!!

The steering performance is much much better than ever before.
THE BELT IS TIGHTEN-UP PROPERLY.
PROBLEM IS SOLVED.

SPECIAL THANKS TO UNCO & PROJRCT TRUENO WHO RESPONDED WITH THE INFORMATION REQUIRED.
 

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Discussion Starter #17
Last Question to project trueno

Unco flush it and feel the difference, in my case powersteering fluid was too dark nearly black as compared to the fresh golden/light amber one.

Last question for Projecttrueno:

Today we tried circling around in a open parking lot with steering locked at extreme right and extreme left position, with engine properly warmed up (coolant temp 190 deg C) the engine revs at almost contant 1370 to 1420 RPM at nearly constant speed of 8~10 MPH with a very smooth, i mean very smooth sound like hhhmmmmmmmmmmmmm. This may be because of entrapped air has been released by flushing with pro-flushing-agent and re-topping and properly tightned belt provided adaquate tension.

I guess it's normal until we hear screeeeech again!!! :)
 
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