I have a 1979 case 580c extendahoe that I bought last year to build my half km driveway and yard, the machine worked great ive put hundreds of hours on it since ive owned it without any real problems. But when I first got it I was driving it around without latching the hoe in not sure if this is what caused my problem or not but about a month after I got it, it started loosing hydraulic pressure when I let it sit overnight, the bucket will slowly lift up (I can actually watch it go up) as im running it and the hoe will slowly turn one way while running. Ive been using it this way for awhile now and its time to get it fixed but where to I start? This is my first tractor so I have a lot to learn but I have no idea where to start
You need to put a pressure gage in the test port and see what the system backpressure is with no circuits activated. Sounds like you have a big enough restriction to flow to create enough pressure to raise the loader from minor leakage across the reliefs in the loader control, this is a serious problem if I am correct since the loop circuit internal to the valve would be at a pressure which is much higher than normal. The boom drift if being powered around is most certainly caused by oring failure on the regeneration checks under the secondaries, a common failure. Don't just do one, do them all, secondary orings as well, you will probably find rings completely gone in there. This one is a tough one , an unusual complaint. Could there be a quick coupler partially blocked by debris from cylinder packing failure, that would be rare but just throwing it out there. There is a normal amount of system backpressure but yours evidently has way more than normal. Maybe alrman can shed some light on this one. Mel
thanks. looks like I am going to have to hire some help
Welcome to HEF Cdnky! When you say "the bucket will slowly lift up", is that the loader bucket, going up while using the hoe?
alrman, that is not the impression I got from his post but if so puts a whole different wrinkle on things. My impression was that it just raises when the engine is running. We'll have to wait on his response as a loader valve issue could cause it if raising occours while the hoe is being used. Good thinking on your part and maybe an oversight on mine. Good to have you back in the groove after your recent trip. Mel
Yes it is the loader bucket, and the hoe will slowly creep sideways, all of these problems happened at once.
Likely you have the same problem in 2 different valves. As Melben said, the load checks in the backhoe control valve will need to be resealed to stop the swing problem. This thread will assist - And this one - HeavyEquipmentForums The loader raising problem is hopefully the same issue but these loader valves are configured very differently to the Backhoe valve. There are 2 different types of Loader control valve fitted to the 580C - Parker & Hydreco - can you look at yours & tell us what type you have & if it is 2 or 3 spool.