I worked on a Cat 305 excavator,serial number 305CDGT01218, the other day that had a hydraulic oil leak. The head had broken off on one of the allen head screws that hold the pilot spool cap on the control valve. It was on the left swing section, I replaced it and sent the machine on it's way. Less than an hour later a screw on one of the travel spool caps broke. I checked pilot pressure and it's at 500 psi. The local Cat dealer installed a thumb on the machine a short time ago. I'm thinking maybe there is a blockage in the system causing a pressure spike, enough to break the screw head off? Does anyone have a hyd. schematic for this machine? I'm also wondering about a plumbing scematic for the thumb? Or any other ideas?
Good day sir We have had a similar experience with spool cap studs, our experience was that the pilot pressure exceeded the correct level. I would suggest that when certain applications are implemented the pressure may well cause the issue. Could we recommend a pressure gauge installed to the pilot system at the caps and observe the pressure when operating the machine. Come back to us at bucketsense@gmail if we can help you further. kind regards Uffex
I had a little time to look at this machine yesterday. The thumb pressure was set at 2500 psi so I dropped that down to 1800 psi. I hooked up a gauge to the pilot pressure test port and ran the machine, hoping to be see a pressure spike but saw nothing over 500 spi. They are going to operate it on Thursday so I'll try to keep an eye on it then.
You have tried so many possible way to solve this issue, now I am thinking what else we can do?You already put the pressure form 25oopsi to 1800psi ,that a great deal,you have done.Googling and asking with expert for this problem.:notworthy
I check with the operator again and so far everything seems to be OK. So was it the thumb pressure being to high or just a fluke that two screws broke? This may be just one of those, "we may never know" times. Thanks for the help.