My 1987 580K is working quite well. (Pre JJ serial No.) It makes good power and all of the functions seem smooth and strong. However I started getting a hissing sound coming out of the rear of the machine, I believe at the backhoe control valve area. The hissing gets louder as the system warms up. It temporarily stops while moving the loader controls but then immediately returns. I suspect I picked up some dirt with one of the stabilizer cylinders which had been leaking and had a rotted wiper. I have since repacked the stabilizers and most of the other cylinders, changed the fluid and filter. I didn't expect it to go away on its own but was kinda hoping... LOL. I have the factory service manual, from which I am trying to understand the flow chart. The case parts website has some insightful diagrams too but I am new to hydraulics. I believe I need to disassemble the backhoe control valve to clean and check for debris or damaged pieces inside. I'd love to hear your thoughts and have a couple more specific questions: 1) Does operating the FEL disrupt flow to the backhoe control valve, hence the temporary pause in the hissing sound when using the FEL? 2) Should I remove the valve body from the machine and separate each component (i.e., inlet, each circuit, outlet) or can I do one circuit at a time on the machine and blow them out with compressed air? The manual says the valve body weighs about 120lbs. 3) Is there another component I may be overlooking? I put a stethoscope on the valve body while it was running but could not determine an exact source of the noise. Thanks, Kevin
I wouldn't be in a rush to remove the control unit and dismantle it. You can work on each control from the top and bottom right on the machine. Take some time and try and isolate the area the noise is coming from can't help you because I've never had a hoe make a hissing sound relief valves only and they squeal but maybe you and a hissing one ?
Is it not doing anything it should, or, doing anything it shouldn't?
Mitch, the machine seems to perform fine. It just makes a constant hissing noise when running.
A hissing noise would normally indicate that there is some oil moving or under pressure. Do the control levers all feel normal? Properly neutralised? Not binding? Foot pedal/s for extendahoe or swing included? Also check all the spool end caps for tightness, I have seen them come loose & allow a spool not to be centred correctly.
Try bottoming out each cylinder and see if another function tries to move, such as when you bottom out the crowd cyl. and hold it does the bucket, swing or boom move? If either one or more do then the load check O-rings are bad and will have to be replaced.
relief valve, crimped metal tubing
Well, I'm finally getting back to the machine. Thanks for the replies. I appreciate them. Since I last posted there have been some new developments. Now the BH controls don't respond with much power and all the BH cylinders move much slower than before. I used the machine to last fall for about 16 hours. At one point the noise seemed to go away for about 10 minutes and the boom and swing controls got more responsive but then the problem got worse and I started getting some unexpected movements such as Coy advised to be on the lookout for. I suspect something moved into a new area of the valve body. I just removed the BH control valve and swing sequence valve out and plugged up all the lines with the correct JIC plugs and caps. I brought the entire valve bodies home and I'll be taking each section apart 1 by 1 after cleaning the outsides. The control valve bodies are not super dirty and no leaks which look serious. The Boom and Swing valve caps look little wet. I'll post updates asap. I will also post when I resolve the matter in case it helps anyone else out. Thanks, Kevin
My first suspicion is a hydraulic suction screen blocked. I often make the point there is no such thing as vacuum. There is only a partial absence of pressure. From the reservoir there is only a pressure differential from reservoir to pump. If the pump makes vacuum, but the screen won't allow atmospheric pressure to push oil to it, it gets gasses dissolved in the oil, or air leaking from small holes in the suction system. Pump runs with a bit of oil, makes a howl.
Anti climatic update: I cleaned and changed all the o-rings in the bh control valve and re adjusted the linkage to the swing sequence valve as per the book instructions. In addition to the hissing in the BH control valve area, there is also a noticeable load on the motor when the machine is running and every control is centered. However, if I move the lift/lower the loader or curl/uncurl the bucket the load and hissing goes away and the engine rpms come up. As soon a I let go of the loader controls the hissing and load on the motor comes. These are open center systems and the only thing I can think of that would cause a hissing and load would be a control valve open but everything seams to be centered properly. I really need to learn a good hydraulic trouble shooting sequence. I made 2 youtube videos to illustrate the load and noise issue. If the youtube links are not displayed, the channel is called PartsisParts.
I never could adjust the swing sequence valve the way the book said to do it. I always adjusted it by trial and error. How does the boom swing, does it swing equally both ways?
It does swing equally both ways. Im going to be looking at the machine this week. I’ll take a stethascope and laser thermometer and try to pinpoint the location of the noise more precisely. Stay tuned.
I've had two 580K, early series & close serial numbers. One was extend a hoe SAE joystick control. The other was three lever, foot swing. I couldn't learn to love the three lever unit & the machine was very low hour, in nice shape. Switched dippers & control tower, replacing pins & bushings in the process. It was a BIG job, I don't think I'd do it again. Both machines had issues with the swing proportion valve. They get corroded & a spring breaks. Easy rebuild once you get it out of the tractor.
What were the symptoms that prompted the swing valve rebuild? I didn’t rebuild that yet. The bh control valves were quite easy. I wouldn’t take the bh control valve assembly out of the machine again either. Just change everything in the tractor…
It'd swing too fast, bang the stops swinging one way, very slow to swing the other way & wouldn't swing all the way.
To close this issue of hydraulic hissing and a drag on the engine, I found the problem. My FEL has a 3 spool valve. The 3rd spool valve is for a clam bucket which is not installed and the lines are capped off. Somehow, the clam spool valve linkage was partially engaged and seized up, causing the valve to partially open. When I removed the linkage the load on the engine cleared up and the noise went away. Everything is back to normal now.
A lot of operators don't use float on a skid steer and the linkage seizes up. It's good to move levers periodically even if they aren't used. You can do it with the machine shut off. Putting some lube on the linkage occasionally is a good idea too. Not too much so it attracts a lot of dirt.
Does anyone know if I can service the swing control valve on a Case 580N without removing the entire control valve body from the backhoe? If so, any tips that would make it easier would be appreciated. Thanks
What is going on with swims circuit?
Boom is quite aggressive left to right and doesn't stop as smoothly as I'd like. Just recently bought the hoe and haven't had much opportunity to use it so there is a high possibility that the trouble is with the operator not the swing dampening valve. Hoe has 4800 hours on it so may be time to change O rings etc. Thoughts?
Check to see if the roller is following the cam on the top pin. If not the check and see if spool is stuck in swing sequence valve. If machine has set awhile it could be stuck. Also check the bolt that holds the top pin in place, it's a 1/2" bolt sticking through the pin.
The fussy linkage Coy speaks of is a challenge. Mine were both 1988 models, close serial numbers. They had notoriously fast & unpredictable swing mechanism. Backhoe valves have challenging plumbing. pressure from the pump enters the seven section valve bank. Don't touch the valve levers, oil flows through & back to the tank. open any valve, oil flow is reduced to downstream spools. Two functions at once, feathering grooves allow some flow to downstream valve sections. Speed of swing is influenced by what other sections are in use. Speed of swing is scarry fast if nothing else is in use. If allowed to swing unchecked, it'd break as it reaches end of travel. Swing sequence valve slows it at end of travel.
Didn't Case have an optional hyd. setup that made the swing too fast to control properly?
Thanks guys for the information. If I need to pull the spool for inspection, do either of you know if I can access the cushion valve without removing the whole valve control? Do I need access to both top and bottom of valve to disassemble? Appreciate any tips.
Don't know. They experimented with flow restrictors in the lines to the swing cylinders, & later 580K had larger swing cylinders moved more slowly as it took more oil to swing. Must have worked it out, 580 SN (mine at least) has pilot controls. It is easy to move very gently, or quicker if you want. It also has power lift, increases hydraulic pressure briefly.
My "N" hoe has pilot control as well. I used a number of mini-ex machines prior to getting the hoe, and some older models, still had the old stick controls. They were a bit rough for sure and going to pilot control was a heck of a difference. Willie, does your SN have a flow regulator valve that allows you to adjust the sensitivity/response of the pilot control to make dipper arm and swing tower move faster or slower as needed?
I believe the hammer circuit only. Mine has an extra two hoses at the backhoe bucket for a hammer, tree grinder, or whatever. I'd like a hydraulic thumb. Case parts to convert to a two way flow prohibitive.
I'm with you there. I have some fence lines and road brush to clear, and a thumb would be great. Priced one here a couple of weeks ago. Run anywhere from $5000 to $8000. depending on whether hydraulic or mechanical jaw. I'm sure you'd spoil $10,000. by time hoses were added and dealer installed it. I'm hoping I can find a good used one at a wrecking yard that I can modify, if necessary, and install myself.
I built my own for the 580K. It had a third valve for the loader, so I rerouted flexible hoses from the loader valve to the backhoe. Two long flexible 3/8 hoses were the hydraulic portion of the thumb. Mine had extend a hoe, so a bit more complicated. Thumb shared the pin with bucket links. I made new, longer from ?4140? steel. I wanted the bores in the thumb to be perfectly perpendicular to the faces of the thumb, so turned the bores of the thumb on a lathe after they were welded up into a unit. My lathe has about 19" swing. The assembly was WAY out of balance, turned it slow, it worked fine. Took some labor, but actual cost maybe $600.
Lucky you had a valve available for the connection. Don't think that is an option for me. Need to check it over to see if I could splice in somewhere or add a valve without too much difficulty. I guess another option would be to go with a mechanical thumb. Not my preferred choice, but better than nothing. Nevertheless, you saved a pile of dough fabricating your own rather than going with OEM. Excellent result.