Squeal coming from Power Steering Pump under load

[matthud]

When I put load on my power steering system by turning the steering wheel when the car is sitting still with the engine running, it seems to load up the power steering pump and cause a lot of noise. It appears that the pulley actually slows down and I think the belt starts to slip. What is causing the pump to load up this much. Could there be something wrong with the pump? It was doing this last fall, and I just replaced the assist ram, the hoses, and rebuilt the control valve. I bled the system and balanced the valve. The noise goes away when the car is moving forward and turning because there is less resistance. Where should I focus my attention?

 

[Bob Chadwick]

I know it''s obvious but belt tension is the starting point.

 

[matthud]

Whats the proper way to make sure the tension is right?

 

[muddywaters]

Tire pressure?? The belt should have about 1/2 inch of deflection....

 

[toobroketoretire]

Proper belt tension for the power steering pump

Because of where it's located, it's very difficult to tension the belt. You can screw a bolt into the front of the top of the pump to provide a pry point, and when you're done, just leave the bolt in there (for the next time). I found that 3/8" bolt hole years ago when the light was just right, and quickly screwed a bolt into it.

 

[matthud]

Tire pressure?? The belt should have about 1/2 inch of deflection....

1/2 of deflection with what kind of force on the belt?

 

[toobroketoretire]

1/2 of deflection with what kind of force on the belt?

Moderate pressure. Maybe a 25 pound pull on a 2 foot long bar. Enough to give the short belt a bit of a "twang" to it. Like I said in my recent post, I discovered an unused 3.8" tapped hole in the front of the pump just above the pump's nose. I screwed a 3/8 USS bolt into that hole and left it there. As the bolt is above the pump's nose casting, it gave me an excellent place to pry on. I used to have go under the car and find a pry point down there.

 

[Bob Chadwick]

1/2 of deflection with what kind of force on the belt?

The force on the belt is defined by the deflection. Too much force and you get no deflection and premature wear of the bearings. Too little and you get belt squeal and loss of efficiency.

Pry back on the pump until the deflection is 1/2 inch and tighten the bolt. As I recall the belt is fairly short and doesn't require much force. Be careful where you pry so you don't damage the pump.

 

[KOPBET]

My two cents...

It it has been slipping a bunch, change the belt. Make sure the new belt is correctly shaped (cross section) for the mating groove in the pulley(s) and pulleys are clean.

 

[KANE]

Because of where it's located, it's very difficult to tension the belt. You can screw a bolt into the front of the top of the pump to provide a pry point, and when you're done, just leave the bolt in there (for the next time). I found that 3/8" bolt hole years ago when the light was just right, and quickly screwed a bolt into it.

I've ++carefully++ used a mattock pick handle between the shaft on the pump and the balancer. Might not be the school house approach... but it works.

 

[matthud]

My two cents...

It it has been slipping a bunch, change the belt. Make sure the new belt is correctly shaped (cross section) for the mating groove in the pulley(s) and pulleys are clean.

How many different type of v-groove belt cross sections are available? I am running Dayco belts that are less than 200 miles old. Dayco 15435, which is a 36 degree, 0.44 top width belt.

 

[KOPBET]

Don't know how many there are, but I do know that there are differences. I had significant difficulty removing and replacing my P/S belt even when all the available slack was given and I couldn't immediately figure out why. I later discovered the belt that was on the car when I bought it had a "V" that had a depth of about 7/16s of an inch and the correct belt only had a depth of about a 1/4-5/16 of an inch. Width was about the same. That two-three extra 1/16s of an inch caused an internal diameter difference that made enough to cause difficulty removing and installing the belt. Additionally, the belt did not properly fit the "V" in the pulley so the belt due to the depth of the "V" and would not sit down in the groove like it should which in turn also changed the separation distance of the pulleys. This in effect "shortened" the belt by about a quarter inch. Proper belt, no more problems.

 

[matthud]

What brand belt did you end up getting that was correct?

 

[KOPBET]

What brand belt did you end up getting that was correct?

It's a Dayco belt. If I remember correctly I got the number from the AIM or parts catalog and ordered it from one of the Interweb Corvette stores. Seems like it was either Dr. Rebuilt or Corvette Central. Don't remember which.

 

[73shark]

I've ++carefully++ used a mattock pick handle between the shaft on the pump and the balancer. Might not be the school house approach... but it works.

Not a good idea to pry against the harmonic balancer as the outer ring is bonded to the hub and isn't designed to have external forces placed upon it.

 

[matthud]

I replaced the belt with a gatorback tonight and hit it with some belt dressing prior to installing it. Tensioned it correctly and the squeal went away. There is no slipping now when the power steering pump is loaded.

Thanks all