Power steering pump going bad?

[tsr2185]

91 350tbi

Had a belt/pully squeel a few weeks ago and replaced belt. The squeel didn't really stop. I've got a mild leak on what I believe is the high pressure hose for the steering pump. I plan to replace both lines soon but wondering if I need a new pump aswell...

This morning was the second time I started truck, let it warm up (35f outside) went to turn the wheel and had resistance/no power steering for 2-3 seconds turning both ways. After that it was fine. Only happened twice, both on cold day cold starts.

Starting to believe the cold start squeel is from the PS pump.

Any thoughts, troubleshooting techniques for this?

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[RichLo]

PS pumps usually make a howling noise when they are starting to go bad.

your dry start sounds like air in the system or just really old fluid.

Either way, PS pump are around $50-100 after a core return, up to you if you want to replace it while your in there. But note that I have had a pump be bad right out of the box and went through a bunch of fluid thinking it just needed to be blead more before I finally returned it and tried another one.

 

[Schurkey]

1. Belt tension correct?
2. Belt tensioner worn-out (tensioner bounces up and down)?
3. Belt worn out? (tensioner marks beyond service limit; belt ribs too short)?
4. PS pulley worn out?
5. PS pump pressure valve sticking (debris in pump)?



I have a Trailblazer that in winter requires GM "Cold Climate" PS fluid, or it whines like a three-year-old-girl. But I never had a problem with lack of assist. Dropping the original fluid in favor of the Cold Climate fluid fixed the whine like turning off a light switch. I leave the Cold Climate fluid in the system year-round.

I've never known a GMT400 to need Cold Climate fluid; but anything is possible.

 

[thinger2]

Everything already said.
If you have leak in a hydrualic system, It will also suck air and dirt.
That air puts moisture into the system and dirt and grit is not good.
When it sits overnight, that frothed foamed air goes from an emulsion to a bubble that gets trapped in a corner someplace in the system.
It comes out of suspension.
When you start the truck again, The pump mixes that air back to being an emulsion.
But it takes a while for that to happen.
If really want to see this in action.
Make some red wine and olive oil vinegrete for a salad.
Whisk the hell out of it.
Stick in in the freezer and try to whisk it again.
That said , the other thing to look at is pulley alignment throughout the entire system.
And wear on all of those pullys.
Take the belt off and start wiggling things around.
Use a good straight edge.
Any play or slop that you can feel by hand is too much.
Dont concentrate on any one particular part of the serpentine belt system.
Look at it and diagnose it as an entire system.
Any type of failure in that system will rip everything else apart.
One bad tensioner, one wobbly pully.
That load gets transferred to something else.
But they will run forever untill the whole thing blows up.
Fix the one bad part so you dont have to fix all of the parts.

 

[97Burban57]

Just changed my power steering pump, use a mechanical stethoscope to narrow down where the sound is coming from. For me the whining off the power steering was obvious.
Your leaky high pressure line could be from the rubber o ring going bad inside, may just need a new o ring to stop the leak.

 

[east302]

Another potential source of belt squeal is the pulley flange not being flush with the PS pump shaft.

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[tsr2185]

Just changed my power steering pump, use a mechanical stethoscope to narrow down where the sound is coming from. For me the whining off the power steering was obvious.
Your leaky high pressure line could be from the rubber o ring going bad inside, may just need a new o ring to stop the leak.

Looks like it's leaking from the crimped fitting on the high pressure line.

 

[tsr2185]

1. Belt tension correct?
2. Belt tensioner worn-out (tensioner bounces up and down)?
3. Belt worn out? (tensioner marks beyond service limit; belt ribs too short)?
4. PS pulley worn out?
5. PS pump pressure valve sticking (debris in pump)?



I have a Trailblazer that in winter requires GM "Cold Climate" PS fluid, or it whines like a three-year-old-girl. But I never had a problem with lack of assist. Dropping the original fluid in favor of the Cold Climate fluid fixed the whine like turning off a light switch. I leave the Cold Climate fluid in the system year-round.

I've never known a GMT400 to need Cold Climate fluid; but anything is possible.

New belt and checked all pullys for play and resistance before putting new belt on. All were good. The tensioner, well. Got a lot of tension left. It also is dead stable when running.

 

[tsr2185]

Everything already said.
If you have leak in a hydrualic system, It will also suck air and dirt.
That air puts moisture into the system and dirt and grit is not good.
When it sits overnight, that frothed foamed air goes from an emulsion to a bubble that gets trapped in a corner someplace in the system.
It comes out of suspension.
When you start the truck again, The pump mixes that air back to being an emulsion.
But it takes a while for that to happen.
If really want to see this in action.
Make some red wine and olive oil vinegrete for a salad.
Whisk the hell out of it.
Stick in in the freezer and try to whisk it again.
That said , the other thing to look at is pulley alignment throughout the entire system.
And wear on all of those pullys.
Take the belt off and start wiggling things around.
Use a good straight edge.
Any play or slop that you can feel by hand is too much.
Dont concentrate on any one particular part of the serpentine belt system.
Look at it and diagnose it as an entire system.
Any type of failure in that system will rip everything else apart.
One bad tensioner, one wobbly pully.
That load gets transferred to something else.
But they will run forever untill the whole thing blows up.
Fix the one bad part so you dont have to fix all of the parts.

U might be onto something with air in it. Altho I don't see the fluid frothy when I checked it, the issue started a few drives after I topped the PS fluid off. Wonder if cleaner fluid knocked something loose and got it sucking air somewhere. I think my first plan of action is a new pressure line with a flush. The line is leaking right at the crimped fitting on the hose. Everything below it is soaked with PS fluid for who knows how long. That particular hose looks fairly new compared to the rest of the PS system.

 

[tsr2185]

Anyone have a good reference for flushing the PS system? I assume it'd just be best to replace both hoses being I'm replacing one already.