LDS Hydraulic Pump Powering a Hmmwv Hydraulic Winch

[gringeltaube]

That may be your problem. You're trying to push 5 gpm into a 3.5 gpm winch...

Ty, I think you are getting close now...

Normally, with a PS-system - and not steering- the pump's full capacity can flow almost unrestricted through the control valve body and back to the reservoir. On the other hand, when steering hard all the way against the knuckle stops the valves are fully closed and that's when the pump produces that distinctive hissing- or maybe even whining sound.

In post #5 the OP says the noise seems to quiet down some when operating the winch. And we also heard it gets louder at higher rpm, while the winch is not being used.
Which would indicate that this is not a problem of cavitation, but simply too much restriction...!?
So maybe you are right, and he just needs to bypass that "restrictor", somehow?



G.

 

[gimpyrobb]

Or make a bypass loop till the winch is used.

 

[gringeltaube]

... which makes me want to study that TM and see how it's actually designed to work: power steering- AND power brake booster - AND the winch; all on the same pump!?



G.

 

[welldigger]

... which makes me want to study that TM and see how it's actually designed to work: power steering- AND power brake booster - AND the winch; all on the same pump!?



G.

It's actually a common set up in the light truck world. Except the steering box is tapped and the winch is plumbed into the box.

 

[rustystud]

On our busses the hydraulic system powers the steering and radiator cooling fan. The return lines all come together at the oil cooler, then go to the filter which then dumps into the tank just below the full line. The tank is also taller then it is wide. M16ty is right, you need a "T" for the lines to come together at, and then drop the fluid into the top of the tank. The way I would run the lines is this. After the return lines come together they would go to the oil cooler and then the oil filter and then back to the tank at the top. I built my own system on my old IHC dozer like this and it worked great for decades.

 

[Lieutenant Dan]

Well the power steering isn't hooked up yet and I won't have any of the parts for a few months.

Here is the schematic of the plumbing on the hmmwv and the restrictor. The way the restrictor is placed I'd believe that only affects the flow out of the winch not the bypass circuit. I couldn't be sure of that unless i took it apart but the bypass wouldn't flow through the motor.

 

[Lieutenant Dan]

So I guess before I do anything I should just take the winch out of the loop and let the pump go straight back to the tank and see if the noise goes away? If that's the case I can put in a selector valve. One way the winch is in the loop the other way it free pumps or eventually just runs the power steering.

Also on the tank modification..... you guys are saying to move the return to the top? Or should I move the suction too and up the size of the port and the hose?

I really appreciate the help guys! Saturday I was ready to take it all back off and completely give up.

 

[red]

Moving the suction line as well would allow for the best flow/cooling with your tank.

 

[Lieutenant Dan]

The more and more research I do I'm coming with the winch valve body is the restriction. Apperently alot of guys have drilled out the restrictor or removed it and are running upwards of 20 gpm pumps. The valve body supposedly only flows 3.5 gpm max. Guy's make their own manifolds and run a lever in the cab to control the winch. It's either this or my pump is bad.

 

[gimpyrobb]

What are the numbers on your pump? That should tell us what psi and flow it has. Can't hurt to double check it.

 

[Jeepsinker]

Pretty sure the restrict or limits the flow to the winch to keep from destroying it, kind of like a hydraulic shear pin.

 

[Lieutenant Dan]

My pump is 5 gpm and 2000 psi. I don't have the exact pump number off hand but that is what the output is.

 

[Lieutenant Dan]

Yeah that's exactly what it's for. If taking the winch out of the equation makes the noise go away I'm going to have to put a flow controller in it. I really don't want to take out the restrictor although doing so will only make the winch faster not stronger since gpm determines the speed and psi determines the stength.

 

[m16ty]

Pretty sure the restrict or limits the flow to the winch to keep from destroying it, kind of like a hydraulic shear pin.

Flow restriction won't limit your line pull (and work as a shear pin). You'll still have full system pressure, just at a reduced flow. A pressure relief valve is what prevents hyd overload. All a restrictor will do is slow it down.

You could add a adjustable flow control valve and tune the flow to your winch's need. Or if you're thinking on add PS later, you could add a flow divider and just dump the excess back into the tank until you tie the PS in.

If you don't use a proportional flow divider, you won't be able to use your winch and PS at the same time. This may not be a problem if you don't plan on steering and winching at the same time but it's something to think about.

 

[rustystud]

So I guess before I do anything I should just take the winch out of the loop and let the pump go straight back to the tank and see if the noise goes away? If that's the case I can put in a selector valve. One way the winch is in the loop the other way it free pumps or eventually just runs the power steering.

Also on the tank modification..... you guys are saying to move the return to the top? Or should I move the suction too and up the size of the port and the hose?

I really appreciate the help guys! Saturday I was ready to take it all back off and completely give up.

Your new picture-diagram is what I would do to your tank. That way the fluid has a chance to cool even more before being used again. How are you running the cooler and filter lines ?

 

[Lieutenant Dan]

Right now the cooler is after the winch before the tank.

I'm thinking about getting a adjustable flow control to put before the winch.

 

[Lieutenant Dan]

Ok so maybe my pump is no good. Idk I'm ready to take it off and chuck it....... I got home from work and took the winch out of the loop. Same noise little lower rpm. When the truck is idling its making 100psi and actually at the end of the video if you watch the gauge it goes lower when it starts making the noise. Idk what else to do. By taking the winch out its proven it's not a flow restriction. I'm starting to think the pump is no good. Any help please!!!!!

LDS Pump Whine 3: http://youtu.be/Bv1X71WBNZ0

 

[m16ty]

I'm pretty sure it's a cavatatation issue in the latest vid. Look inside the tank and see if you see a bunch of bubbles.

Where was the gauge connected?

 

[Lieutenant Dan]

The tank is always foamy. I took the pressure and return line off the winch and put a tee in the put the gauge on the tee.

 

[rchalmers3]

If the cavitation is occurring with the pump simply sucking and returning the oil to the tank, I'd suggest a larger suction hose with easy bends (45* or less) in the fittings. I'd also fit a better designed tank with increased depth, volume and distance between the suction and discharge ports.

Rick