97 Grand Prix GT Power Steering grunt

[olopezm]

Hi guys,

so I installed a new rack and pinion, new pressure and return hoses in my car and I got a loud grunting sound and vibrations when turning the wheels.

I was thinking the pump was bad so I had it checked and it turned out the impeller had 3 small cracks on it. Since I had another pump lying around I had it checked too and was fine so I went ahead and installed it. Now the steering is very soft (like it's supposed to) and the vibrations are gone but I kept hearing this grunting sound specially when the wheels are about to reach the stops (I'm not hitting the stops).

I've uploaded a video about it here:
http://www.youtube.com/watch?v=Q35EbhjIeHE

From time to time I can see the PS pump pulley kinda wobbling during the grunting so I don't know...

Let me know if you have any ideas. Thanks in advance

Oscar.

[gmtech1]

Sounds like there is air in the system and you need to bleed it out. Key off, ft wheel off the ground, turn steering wheel side to side ALMOST to lock each direction. Do this several times (10 or so) then stop and check the fluid level, repeat this process a couple of times. Some fluid may get pushed out of the resivoir and the air is forced out. After no more air bubbles are seen and the fluid levels out, start the car check your sound. It may take a couple of tries.

[olopezm]

Thanks!

I did bleed the system several times, one with the wheels in the air. When I looked at the reservoir I didn't see foamy fluid but I guess I'll give it another try.

Oscar.

EDIT Forgot to say that the noise doesn't seems to happen when the wheels are off the ground.

[olopezm]

As extra information this did not happen before installing new components with either pump; that's what gets me confused.

Every time I had to open the system and bled the air out this never happened before.

[Tech II]

Run it with the cap off.....see if the level drops when turning it to the stop...

[olopezm]

Couldn't take some time to check the car; maybe tomorrow.

In the meantime I've been thinking, shouldn't the noise be constant during the entire range of the steering wheel if the problem was air in the system?. I can only hear it near the stops (NOT AT the stops).

Thanks,

Oscar.

[olopezm]

So I repeated the bleeding procedure and nothing changed...

I checked and the level does not drops when the chattering occurs. I noticed the PS pulley sometimes moves when the chattering is present but what surely has me stumped is the fact that the pressure line (brand new) VIBRATES along with the noise and that's where the noise seems to be coming from.

I also noticed that the problem gets worse as the engine reaches normal temperature. Every cold start there will be no noise and the wheels will turn smoothly, this starts to change as the fluid temperature raises.

Do you have any other ideas? Why is the pressure line vibrating?

I would like to wish you all a MERRY CHRISTMAS. Thanks in advance...

Oscar.

[gmtech1]

Where did you get the new rack? AZ or Napa? I have had LOTS of problems with the rebuilt racks causing all sorts of problems. You said the noise was not there before you replaced the gear, that is was quiet with both pumps? After all that bleeding I doubt there is any air in there. You may have a problem with that gear.

[DeltaP]

Sure sounds like air to me. Try the same aformentioned proceedure again but this time with the engine running. You can hit the stops a few times just to get the feel of when to stop but then turn it end to end just before the stops, holding it there each time for about a second. Hitting the stops just opens the relief valves and does nothing to bleed the air out. HTH

[olopezm]

Thank you guys!

gmtech1:
I did not replace the rack, I got mine rebuilt. Actually, when the guy took it apart in front of my eyes it was fine, the shaft had a nice mirror finish and only a minor "scratch" caused by water intrusion through one of the boots. Honestly I don't know why it was leaking... Since it was already out I decided to have it rebuilt so I wouldn't have to deal with it again. Do you still think it the rack could be the problem?.

Before that I kept having a whining sound coming from the PS pump all the time which would go up and down with RPM's with every single pump I installed. That's why, at this time, I decided to replace all of the steering system items.

I had a steering pump lying around in the garage which I took to the same guy to have it tested. He took it apart and pressure tested it, it was fine. It's the currently installed pump, the old one had some cracks on the impeller and was said to fail sooner or later.

DeltaP:
I did the procedure with the engine running but didn't hold it for about a second, only kept turning the wheels constantly from side to side without hitting the stops. I guess that's the flaw in my bleeding procedure... Will definitely give it a try.

If you have any other suggestions please let me know.

Oscar.

[Tech II]

Seem to remember a TSB about PS hoses causing this problem.....

[olopezm]

I checked all TSB's related to my car in Michell On Demand and the only one mentioning the line replacement applies only to 3.1 engines. Thanks anyway.

Any other ideas?

Happy holidays!

Oscar.

[DeltaP]

We're thinkin'.

[olopezm]

Well, this thing is driving me nuts! I still haven't found the problem and don't know what else to do.

I'll try bypassing the steering fluid cooler and see if that works. Do you guys know of any long term problems about doing such thing?

HAPPY NEW YEAR!

Oscar.

[rickisrad]

check the pulley, going by the video it almost looks like it is pressed on too far. it should be flush with the end of the shaft. to me it sounds like a bad pump bearing or a problem with the rebuilt rack. ........ BTW a dirty or clogged cooler can cause a noise.