Hissing / Screeeeeeeching Sound while steering

[bonnie*]

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???

[Unco]

sounds like the pump itself. have you checked the fluid level? you may need to replace the pump, not just the belt.

[bonnie*]

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???

[project trueno]

^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

[bonnie*]

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?

[Bitter]

could be air in the system? the air cavitating through the vanes of the pump can make some loud nasty sounds.

[bonnie*]

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?

[project trueno]

Originally Posted by bonnie*

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.

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.

[project trueno]

Originally Posted by Bitter

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.

[bonnie*]

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.

[project trueno]

^yes.....just leave that F.. plunger alone. You say your RPMs are not dropping, that means its working PERFECTLY.

[bonnie*]

Tomorrow More Feedback After Tightening Up Belt

[ghost_ryder35]

did you check the fluid level also?

[bonnie*]

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.

[schn0354]

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.

Originally Posted by bonnie*

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.