Equipment Hydraulics

redneckjeep87

redneckjeep87

Landscaper Extroidanaire
Joined
Oct 10, 2007
Location
Woodleaf, NC
I have some tractor hydraulic implements that I am wanting to convert over to run off skid steer hydraulics. 3pt backhoe as well as a log splitter and I'm sure there will be others down the road.

All the implements I am dealing with are 2500psi max cylinders. Have already blown quite a few seals even at idle.

My current machine pressure is 3700 psi with 3 stage flow rate of 3gpm, 13gpm, and 16gpm. It has the standard 2 flat face skid steer couplings as well as a case drain.

I need some sort of pressure reducer setup that ideally I can utilize between multiple implements. Would be great if it was a seperate entity that plugged into both and I can just build a mount for it to sit on opposite loader arm or on the implement.

I know that it is plenty doable, just need to find the right hardware and information. Local hydraulic shop I went to wanted to do some crazy convoluted shit inside my machine with electric over pressure regulators etc etc so I walked to out. It shouldn't be that difficult. Another told me to adjust the pressure relief on my pump when needed and screw that. I swap implements too often on jobsites for it to be that time consuming.

I do have double acting hydraulics so I assume would need to have some sort of one way check valve on the "return" end due to valve block on the backhoe being one directional.

With a pressure reduction From 3700 to say 2350 or 2400 to stay under the 2500psi cylinder pressures, would the excess pressure need to return via the case drain?

I have done quite a bit of looking around on the subject but noone has the info that pertains specifically to my situation for some reason. Also not looking to screw anything up with my 50k machine by going by some hack job bubba on Facebook or down the road told me to do. I trust yall which is why I am posting here. Lots of smart mfers in here.

Machine is a ditch witch sk1550. Out of warranty, paid off next month....finally, not that that part matters.....but wooooooooooo!
 
jeepinmatt said:
@braxton357 knows his stuff on things like this.
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That's why I went to talk to a hydraulic shop.....boy was that a wast of my time.
I know enough to know what I am looking for is 100 percent feasable.......but not what parts to put together to get to that point.....and as reasonably priced and small as possible.

I honestly should have posted in here a long time ago. I got frustrated and put it all on the back burner. I really would like to be able to utilize my backhoe attachment though
 
This depends on what attachments you're wanting to run as well as are you controlling the attachment via its own directional valve or using the skid steer's. Most simply, both your log splitter and your backhoe probably have a pressure relief in the valve stack and those should be keeping the pressure where it needs to be but you may have to tee your return line to the case drain. Otherwise, assuming you're only running the flow from the skid in one direction always--using it as if it's just a hydraulic pump that only puts pressure out of the "a" port and return to tank on the B port then you could buy a 3 port relief like this Adjustable High Pressure Relief Valve, 20 GPM, 2500 PSI, 3/4" NPT and run the inlet to a quick connect that plugs into your "A" flat face on the machine the the outlet to a female flat face your hose would hook to. And the " tank " port to a short hose into your case drain line.


If you're wanting to run the log splitter with the skid steer's aux valve instead of the one on the splitter you'd have to go another route.


:edit: I have a way shittier boxer mini skid and it has like most equipment two hydraulic pumps, one of them is just for auxiliary hydraulics and I can set that prv to whatever pressure I want without affecting the rest of the machine, you should talk to your dealer and see if they can set only your aux pressure to 2500 without affecting lift capacity or anything else, that would be the simplest answer.
 
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@braxton357
Good deal with the link. That's what I have been looking for. And the info I have been looking for that I can in fact use my case drain......you wouldn't believe the amount of people that can't even tell you what to do with it.

Which leads me to the statement of....yeaaaa this thing won't ever see a dealer again. Dwotc pretty much sucks at diagnosing or doing anything other than pulling the trigger on the overpriced parts cannon.

Also use standard miniskid pressure implements so def not looking at adjusting the reliefs on the machine.

Perfectly fine with having a setup like your link. Going to be perfect....except I'll plumb in a gauge more than likely.

I assume it would get pretty Intricate if I wanted to use the actual machine aux controls to run a woodsplitter without its own valving. Obviously would also have to be stepped down. I am fine with running that linked pressure relief with the spool valve on the splitter.........but at some point would like to convert a splitter so that I can just control from the machine
 
Be careful using case drain to run this auxiliary equipment back to tank. Excessive case drain pressure can/will cause input shaft seals to fail. Have seen this often on equipment. if you have an extra plugged port in the hydraulic tank, your better to go straight to tank with your return. Maybe skid steer stuff is different the what we build.
 
Jeff B said:
Be careful using case drain to run this auxiliary equipment back to tank. Excessive case drain pressure can/will cause input shaft seals to fail. Have seen this often on equipment. if you have an extra plugged port in the hydraulic tank, your better to go straight to tank with your return. Maybe skid steer stuff is different the what we build.
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"Case drain" means different things in different industries but in this setup
Only the relief valve would be using the case drain. that being said every case drain motor failure ive ever seen has been someone not plumbing the attachment correctly, there should only ever be a relatively small amount of fluid or none at all on that line and on a skid steer or excavator other than possibly having a filter inline it is run straight to the tank.
Plus there are very few mini skid attachments that actually require one unless maybe he's running a high flow mulcher.
 
braxton357 said:
"Case drain" means different things in different industries but in this setup
Only the relief valve would be using the case drain. that being said every case drain motor failure ive ever seen has been someone not plumbing the attachment correctly, there should only ever be a relatively small amount of fluid or none at all on that line and on a skid steer or excavator other than possibly having a filter inline it is run straight to the tank.
Plus there are very few mini skid attachments that actually require one unless maybe he's running a high flow mulcher.
Click to expand...
I understand. on the stuff we build, the case drain is run through the oil cooler then back to tank. so there is a little pressure there to begin with. Also, the case drain from pump and motors are combined. Typically, when I run into excessive case pressure someone has plumed into it or there is a motor failing. Also, most of our circuits are closed loop. Thanks for clarifying.
 
I can provide the machine hydraulic schematics if that would help? Obviously I do not want to harm my hydraulic pump/system as it would be on me repair wise.

I was under the assumption the case drain was in fact direct to tank. It's been a minute since I sat down in front of the schematic though


I'm not sure if the mulcher my buddy sells has a case drain or not, I'll have to ask him. Osma ssk...... definily isn't one on my open front brush cutter. That sob just needs a secondary cooler in the summer months


I'm ready to pull the trigger on that relief valve as soon as we get this ironed out 100 percent.

Anyone on here have a hydraulic crimper?! Having them built has gotten ridiculous
 
I would like to see the schematic just for having a look, if it's just relief you're more than likely fine like Braxton stated.

You can buy reusable fittings
 
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