I have a 2000 model 555e. I noticed a couple years ago the digging power seemed to be gradually declining. It has now gotten to the point it doesnt dig well at all especially when hydraulics are warn and you try and use multiple digging functions at a time. I have replaced the hydraulic fluid, installed a new suction strainer, new filters, new hydraulic pump, new system relief valve with no success or change to performance. The service manual shows a an anticavitation bypass in the backhoe valve along with all the circuit relief valves. I have not investigated these yet. Just curious before I spend more time and funds on this if annyone has any thoughts or experience? Thanks
What RPMs do you usually run? I have a 98 and run it about 17-1800.
You have certainly spent some money on the fix. I suggest that you follow the NH test procedures prior to spending any more $$. If nothing fails the tests on the hydraulic side, I would look to the engine's ability to make power.
Could have something blocking the strainer filter. I found a rag covering mine. Also could be an issue with getting air somewhere in the system, but I agree with Swetz.
I know you said you replaced the strainer. Did you look close in the hole where it screws on? First time I did mine I found a rubber disc that apparently came loose from inside the strainer and stuck in the opening. My tank also had a couple of paper towels in it but those wouldn't be able to clog the strainer. My machine hasn't ever had the trouble you are describing but I don't know how the rubber disc wasn't causing a serious restriction.