Looking for an excavator for general farm use. Looked at a 1981 koehring 566 the other day. It seems cheap but maybe parts are to hard to get to be worth will getting. I dont understand the way the air hydraulics work? Can someone explain them to me.
It is air over hydraulic controls. They use air pressure to move an air cylinder connected to a spool on the hydraulic control valve. Good machines in their day but you have a rats nest of air and hydraulic hoses and all the problems you normally see with old trucks with air brakes. I've worked on 466 and 666 machines but never seen a 566. Do you have a photo?
Will get some pics. So basically the air system works trouble free except for some air leaks?
I said like an old truck! The hand controls leak, the air cylinders leak, the regulators go bad, there is no feel in the controls, the compressors start making oil, freezing weather means frozen controls and lots of alcohol. We are still on the air system. It gets real expensive once you start working on swing and travel pumps, the center swivel and all the cracks in frames you are likely to see on one of those old dogs. The machine might be all hydraulic control with that year of manufacture but I thought they changed the model numbering system by them. Anyway photos will tell the whole story.
Have some pictures but cant post them yet. Will post as soon as i can
Picture of hydraulics Not to good of picture but one of cab interior Let me know John if you need a picture of something else
Hey farmlion where in Manitoba are you? I'm in St. Pierre about a half-hour south of Winnipeg. I worked with an old 866E years ago and you could hear the air system working sometimes over the screaming Detroit. Did you see a compressor or a big air tank under the hood somewhere?
I'm in sw mb. Yes there's a compressor on the motor. Under the hood on the left hand side there is a big tank. Looks like it's kinda air/hydraulics.
So you probably have to use the toggles on the joysticks to switch from swing to stick etc.? If it's a pain to find parts for you could always look for an older Cat like 215, 225 etc. Or John Deere 690 they all have hydraulic controls that are sorta easier to maintain.
Guy wasn't there when I looked at it so didn't see it operating. So not sure about the controls. I'm sure there is better options but they would be a lot more money. And machine looks pretty good. But maybe not worth the extra pain
Well don't be afraid to look out of province too, lots of excavators in Alberta too.
"If it's a pain to find parts for you could always look for an older Cat like 215, 225 etc." Hey 245dlc. I found a Cat 225LC. Havent been to look at it yet but have some pictures. Anything special i should look at when i go to look? What do you think this should be worth?
That one looks like it has the newer controls? IIRC, the air over hydraulic machines had small air toggles on the handles that you worked with your thumbs for the stick and bucket. The only Koehring I ran (forget the model #) looked like this one, and the controls felt the same as a Cat or Komatsu. Not sure when they switched from air pilot over hydraulic controls to modern hydraulic pilot controls, I don't know if this one's air or not.
Certain 225's depending on where they were manufactured had either a 3208 Cat engine which is a boat anchor or I think it was a 3304 which was a 4 cylinder engine. I'd avoid the 3208 like the plague, that gusset on the stick is a little concerning but if your just using it occasionally on the farm I think it'll be alright.
The 566 in the photo has hydraulic pilots and should be easy to run and not have the same issues of the older air over hydraulic controls. I suspect the big tank you are speaking of is the hydraulic or fuel tank and that there is only a small air tank. The air pressure is used to keep and head load on the hydraulic tank forcing oil into the pumps. Good Luck!
Thanks John. Is there anything else I should know about this machine? Or is there anything else I should look at on it? The undercarraige looks decent and the motor and hydraulic pump are supposed to be overhauled.
Watch the swing gear box make sure it's always got oil, pump drives if they are anything like on the old Cat machines and the rotary manifold. I know a guy with an old Bantam Koehring 366 and he's issues with the swing and the rotary manifold and said that parts are getting pretty hard to find.
If that 225 has a 3208 it'll be just fine for what you're going to use it for. We ran a 225LC with a 3208 for 20 years, and we never really had any problems with it. Most of the time we had an Add-A-Stick on it and it handled it just fine.
I never got to work on the newer models of those machines. The first coal mine I worked at had the old 666 and when I got back to a dealership again the computer machines from Japan had started taking over all of industry. Koehring always built a heavy machine and I haven't seen any problems in the frames and booms of the smaller units. The great big units though did have those kinds of problems. They all were kind of clumsy to run. What is the brand of the pumps in this unit? The older machines had a closed loop swing circuit. Does this one?
Not really sure with that one, I had always heard that Koehring's were very strong machines I worked on a site years ago with an 866E and from what the other operators were saying it mostly just needed the pins and bushings redone. But things do wear out over time.
The pumps are sundstrand. Not sure about the closed loop swing circuit and they were not sure either when i asked. How do I tell? And is that good or bad?
The closed loop systems usually have a lever or controller on a pump and the hydraulic lines only go to the swing motor. With an open loop system one pump would feed a control valve that would divide the oil flow between many different circuits and then return the oil to the reservoir. It isn't really good or bad. Just a different way to run a system. With the type of valves I see in the photos, I would guess this machine is like the rest of the manufactures with a open system.