Power Steering Pump Options?

[thompsoncustom]

Been sound proofing the humvee and the quieter it gets the more I notice the power steering. I was thinking about rebuilding or replacing the pump even tho there is no foam or air bubbles in the reservoir I'm not sure it's not sucking a small amount of air around a seal that I can't see evidence of in the reservoir. When you start it there is no noise at all no matter how long you idle but once it's under pressure you can hear it.

Now the humvee is a 91 m998 I believe that the army rebuilt in 2012 with the 6.5 N/A 4 speed so it is the pump with a reservoir, number on the pump is 12469485.



I was wondering what my options are for pumps out there? I see there are direct replacements on ebay but they want a lot for them so I was wondering if there was a civilian model that bolted up say off of a h1 hummer or older GMC pickup. Also is there a difference is military pump noise do some models make more noise than others?

Also since alot of military stuff is serviceable I can't image it would be to hard to tear it apart and find seals at napa. Anyone had luck rebuilding there pump?

 

[Hummer Guy]

Been sound proofing the humvee and the quieter it gets the more I notice the power steering. I was thinking about rebuilding or replacing the pump even tho there is no foam or air bubbles in the reservoir I'm not sure it's not sucking a small amount of air around a seal that I can't see evidence of in the reservoir. When you start it there is no noise at all no matter how long you idle but once it's under pressure you can hear it.

Now the humvee is a 91 m998 I believe that the army rebuilt in 2012 with the 6.5 N/A 4 speed so it is the pump with a reservoir, number on the pump is 12469485.

View attachment 919113

I was wondering what my options are for pumps out there? I see there are direct replacements on ebay but they want a lot for them so I was wondering if there was a civilian model that bolted up say off of a h1 hummer or older GMC pickup. Also is there a difference is military pump noise do some models make more noise than others?

Also since alot of military stuff is serviceable I can't image it would be to hard to tear it apart and find seals at napa. Anyone had luck rebuilding there pump?

I would look at the PSI and make sure they're the same, but you should be able to make the civilian pump fit, you'll just need to make a bracket for it, anything can be done with some fabrication. Personally, I would stick with the military pump and take the bullet in the wallet.

My pump is somewhat quiet with the system completely bled off properly and with the front tires aired to where they're supposed to be at.

I would also be interested in seeing your other approaches of deadening the sound

 

[Mogman]

Again all gear pumps make noise, that is why you will not find one from "an old GMC truck",, 99% of civy vehicles use a vane type pump because they are much quieter.
I'm sure you could fit a vane style pump from an earlier HMMWV with the built in reservoir but why? gear pumps are more dependable and can make more pressure, that is why they went to them.

 

[thompsoncustom]

ya not sure I would want to go away from the gear pump but gear pumps aren't all that noisy either I have a 40ton and 20ton hydraulic gear pumps on my wood splitters and you can't hear the pumps running and both of the engines make less noise than the diesel.

If these pumps are just a bad design and make a bunch of noise even in 100% working order than I won't waste me time replacing/rebuilding it I'll just soundproof the pump itself just don't want to be covering up a problem instead of fixing it.

 

[thompsoncustom]

I would look at the PSI and make sure they're the same, but you should be able to make the civilian pump fit, you'll just need to make a bracket for it, anything can be done with some fabrication. Personally, I would stick with the military pump and take the bullet in the wallet.

My pump is somewhat quiet with the system completely bled off properly and with the front tires aired to where they're supposed to be at.

I would also be interested in seeing your other approaches of deadening the sound

PM sent

 

[Retiredwarhorses]

I know of no rebuild kit for this pump, the pump is reffered to as the “whiny” pump, for 2 reasons, one because it’s English and the other because it’s noisy. I’ve opened these pumps up, they are like nothing you have ever seen, frankly a marvel of engineering, noise comes from air, if you have no foaming of any kind, just run it.

 

[Retiredwarhorses]

 

[Autonomy_Lost]

ya not sure I would want to go away from the gear pump but gear pumps aren't all that noisy either I have a 40ton and 20ton hydraulic gear pumps on my wood splitters and you can't hear the pumps running and both of the engines make less noise than the diesel.

If these pumps are just a bad design and make a bunch of noise even in 100% working order than I won't waste me time replacing/rebuilding it I'll just soundproof the pump itself just don't want to be covering up a problem instead of fixing it.

If you figure out how to soundproof the pump, let us know.

 

[thompsoncustom]

View attachment 919139View attachment 919140View attachment 919141View attachment 919142View attachment 919143View attachment 919144

Wow thanks for the pics, ya that's not your standard gear pump looks like a vane pump using hydraulic pressure maybe but neat none the less.

Ya sound proofing it wouldn't be easy or pretty i'm sure because of the pulley there won't be a lot room to get much on that side of the pump. I'll probably put a layer of kilmat then Closed cell foam followed by MLV that should block most of the noise if I can fit it all on there. Also that will be to much weight for it to hold itself in place with adhesive so I'll have to wrap the whole mess in some kind of tape, might be a little ugly but should work.

 

[87cr250r]

We despise gear pumps in th marine industry. Too noisy and no benefit. Vane pumps are always an upgrade. They're good for 3000 psi and last longer than gear pumps. If you need more than 3000 axial piston becomes the preferred flavor.

 

[Autonomy_Lost]

So just for the heck of it I added some LubeGard ATF protectant in the power steering reservoir (its Dex III compatible and adds lubricity without affecting viscosity). I've read that others have had good success using it with power steering systems that use ATF.

Anyway, it maybe slightly reduced PS noise at low RPM's, but its still very loud at high RPM's (3000+). Maybe the key to a quiet pump is driving slow.

 

[87cr250r]

Lowering the oil viscosity helps. Dexron 3 would be roughly the equivalent of an AW32 hydraulic oil.

 

[thompsoncustom]

We despise gear pumps in th marine industry. Too noisy and no benefit. Vane pumps are always an upgrade. They're good for 3000 psi and last longer than gear pumps. If you need more than 3000 axial piston becomes the preferred flavor.

Well with the picture above it's clear that humvee's don't use a gear pump at all they have the standard civilian style vane pump and the beefy version of a vane pump pictured above but nothing that resembles a gear pump.

Lowering the oil viscosity helps. Dexron 3 would be roughly the equivalent of an AW32 hydraulic oil.

I'm actually going to be testing that as I had that same thought and I found a Dexron III rated fluid that's low viscosity. It's mobil 1 lv atf hp but if you really wanted to go thin you could try the new Ultra low viscosity fluids but that seemed a little risky to me.

 

[Mogman]

Well with the picture above it's clear that humvee's don't use a gear pump at all they have the standard civilian style vane pump and the beefy version of a vane pump pictured above but nothing that resembles a gear pump.


I'm actually going to be testing that as I had that same thought and I found a Dexron III rated fluid that's low viscosity. It's mobil 1 lv atf hp but if you really wanted to go thin you could try the new Ultra low viscosity fluids but that seemed a little risky to me.
View attachment 919276

I'll be, that is a roller pump not a vane pump, roller pumps are also notoriously noisy.

 

[Autonomy_Lost]

What about a larger power steering pump pulley to slow down the RPM's?

 

[thompsoncustom]

What about a larger power steering pump pulley to slow down the RPM's?

tho that would probably help with the noise it would also reduce operating pressure. I'll change the fluid out and see how it does then I'll wrap the pump in sound deadening material and call it good as it looks like it's gonna be a noise pump by design so blocking the noise is the best option.

 

[Autonomy_Lost]

tho that would probably help with the noise it would also reduce operating pressure. I'll change the fluid out and see how it does then I'll wrap the pump in sound deadening material and call it good as it looks like it's gonna be a noise pump by design so blocking the noise is the best option.

True, but it might not matter. The pump is really screaming at 3000+ RPM. Maybe lower RPM would even reduce wear. Even a 20% reduction would make it quieter and probably not have a noticable impact on performance.

 

[thompsoncustom]

True, but it might not matter. The pump is really screaming at 3000+ RPM. Maybe lower RPM would even reduce wear. Even a 20% reduction would make it quieter and probably not have a noticable impact on performance.

ya your right that's all I'm doing with fluid is making it thinner to reduce pressure.

I wonder if they build them to run way higher than needed at all times so when u use say a winch, outlanders, or whatever they have its not a issue.

 

[Mogman]

ya your right that's all I'm doing with fluid is making it thinner to reduce pressure.

I wonder if they build them to run way higher than needed at all times so when u use say a winch, outlanders, or whatever they have its not a issue.

The hydraulic system on a HMMWV is an "open" system, it has very little pressure until it is called upon to do some work.
It may be quieter with thinner fluid but the system will build whatever pressure is required for the task it is asked to do as long as the pump can supply it.
EDIT, otherwise it is just circulating the fluid

 

[thompsoncustom]

The hydraulic system on a HMMWV is an "open" system, it has very little pressure until it is called upon to do some work.
It may be quieter with thinner fluid but the system will build whatever pressure is required for the task it is asked to do as long as the pump can supply it.
EDIT, otherwise it is just circulating the fluid

but if you change the fluid or pulley wouldn't it adjust the circulating pressure along with the working pressure?