I just bought an old 1975, case 580b backhoe and the backhoe attachment will only swing to the right. If I hold the left foot pedal down to swing it to the left, it will only move if I move one of the hand controls for backhoe just slightly. My thinking is that something is wrong with the control valve for that left pedal and when I move one of the backhoe hand controls, Oil is bypassing and being back fed from one of the hand controls. Does anyone have any suggestions as to what the problem would be. Thanks in advance.
The special o rings on the checks need to be replaced, they need to come from case. Your backhoe has two boom cylinders ?, the hoe is a 35, if it has a single boom cylinder it's a 33. There are several posts on here about replacing them. You will unscrew the circuit relief, reach in the bore with a tool made from a bolt, turn it and pull the plug and poppet out, replace the oring and backup and reinstall. It takes just a few min once you do one and get tooled up. I will try to find the post in a bit, you don't need the bolt tool but it helps. This is where I would start.
Sheepfoot, if you can find any posts on how to install the o-rings in the boom cylinders let me know. I have a similar problem with my 35 hoe. Jamby
While the others are right about oring failure in the check plugs and secondaries, I'm bettin you have a linkage problem not allowing the spool to stroke far enough to send the oil to the cylinder. The clue is when you say it will move when other functions are used as that creates a pressure rise that will allow oil to go through a partially open spool. I have worked on hundreds of those hoes. Take the covers off the lever console and watch the spool movement, Over years the linkage pins and rods wear so the swing pedals lay down to flat. Change the yoke length till the pedals are standing up a good bit, observe the spool stroke to verify it is going full stroke in both directions and try it. The others are right as those valves were hard on orings and they should be checked especially if there is interaction between systems but for starters I would do linkage. I have seen many of that vintage hoes where the lever slots have been lengthened so the other control levers did not bottom against them. Let us know how you make out, there are lots nof good minds on here and we will get you through it. Mel
I have a linkage problem with my 580B . The pins are worn and the pivots on the peddles are worn . I thought about shimming the pedals upward a 1/8 of a inch and drilling the clevis's so as to go to a slightly larger pin. Any thoughts on this? from jerry