Hi, i have an '80s model case 580 super e 4x4 extendahoe, recently the rear boom started falling to the ground! My dad was loading logs with the rear boom, and it got so bad he couldn't keep it up, as soon as he let off the leaver, it dropped to the ground. There are no external xylinder leaks, is there anything i can check or does anyone have any idea as to what is going on?
Leaking piston seal in one or both boom cylinders most likely.
Ok, is there a way to pressure test to see if or which cylinder would be leaking?
There is. But it would be best to just remove both cylinders and reseal them. If one cylinder is leaking that badly then it won't be long until you will be doing the other one. There is a chance you have a problem in the valve bank, but if it were mine I would reseal the cylinders first.
The 580K has a pressure relief valve off center in the aluminum piston. They are prone to leaking. When mine became severe I took it to a hydraulic shop where they pointed out a bullet dent from outside the cylinder. This caused a bump on the inside, which damaged the aluminum piston. The repair wasn't cheap.
The thread is about a 580SE. I would be surprised if the boom cylinder would have an aluminum piston. The parts book doesn't show a valve of any kind in the piston. http://partstore.casece.com/us/parts-search.html#epc::mr103088ar989606
Dunno, just throwing that out. The tractors are somewhat similar, but built in two different countries. The E, if I recall has two smaller boom cylinders, the K has one big one. Perhaps E doesn't use the valve. I presume the K has it, as what you do with the dipper might suddenly overload the boom. To push oil through hoses to allow quick sag avoiding breakage might take too long. Pushing through the piston would be quicker. My theory is these valves see frequent intentional flow, especially if you have an extendable dipper. Either unfiltered debris gets in them, or they wear. I've had two Ks that had to replace this valve. The symptom is sudden severe sag in the boom. Check the parts book. Willie
You are correct Willie in regards to the K series boom cylinder having a relief valve cartridge in the piston. I never doubted you for a second. The E series do not have a relief valve cartridge in the boom cylinder pistons. The E series is whole different boom arrangement with two cylinders a lot of piping interconnecting the two of them. That piping is intricate the way it connects together and makes pressure testing each cylinder independently from the other a time consuming process. That is why I would just reseal the two cylinders to simply eliminate any leakage in the them. Then if the boom is still dropping, the valve bank would be the next place to take a look at.
The boom cylinders on these monsters is at a severe mechanical disadvantage. If you have one more than a few years without blow by it'd be a miracle. I'd guess packing kits to cost under $100.00. Probably sealing is indeed needed.