I was called out to a case 688 last week that the owner said cut out after about 10 minuites of operation. I have repaired a metal pipe that feeds pilot pressure and had worn through. I have also removed and cleand all the control spools and valve blocks in the slew system and replaced the solenoid on the same system. all this and it is still the same. The only thing left is the pump. there is a small amount of vibration , possibly cavitating in the feed line from the pump. Is the pump for the slew a seperate pump as every other service works fine. thanks Paul
Yes the slew has its own pump. They did that so the swing speed didnt change when another function was used.
Yes like goose said, the system is around 61 gpm, main 41 gpm, swing 9.5 gpm, pilot 6.6 gpm. The swing turns at 6.5 to 7 rpm and the flow is not adjustible like some of the other functions. There a test port called M2 on the swing valve, the pressure should be between 340 to 360 bar 4825 to 5100 psi. There is a quick test procedure that was used to set the pressures on the 88 series machines. The pilot pressure and brake release pressure needs to be at the 24 bar also to make the system work. The swing motor could be by-passing also when it gets hot. I would go back to recheck the pilot pressures to make sure they are stroking the valve and also the brake release pressure when the machine starts acting up. IT would also be helpfull to install some plugs on the swing lines to see how much pressure is there when it acts up with a test gauge. How many hrs on this machine?
Was this problem ever solved?? I have the exact same issue with mine, its like a relief valve is sticking open, once the machine is switched off it clears itself and works fine for a little while then cuts out again. Any help appreciated!! Thanks