Hi all I have a 1996 cat 312 (grey market) The original main pump went bad at 4500 hours so I sent to a hydraulic shop for a rebuilt and finally got it back. Today we flushed the hydraulic reservoir, changed the filter and primed the pump with fluid. Turned the machine on and have a ton of air in the system we have tried cracking a few lines to bleed it and it seemed to help a little the machine almost has a pulse while running and if you try a function it will start and stop as if it is taking a moment to rebuild pressure. So what I am asking is there any other way to bleed the system of any air and has anyone ran into such an issue after reinstalling a pump Thanks everyone
When priming the main pump did you crack the case drain plug and fill it with new oil? Sometimes if you remove that plug they will gravity feed with oil from the tank. Post a serial number for more accurate information.
was the pump tested after it was repaired and do you have test results showing that the pump is performing to CAT testing specifications?. You may need to consider getting the pump removed and inspected again or have the pump flow tested on the machine.
I believe the mechanic working on it did Here is the serial number for both the machine and the pump. And thank you Machine serial number : 7DK07017 Pump serial number : 4i7634x
You'll soon know when you check. It means the difference between him destroying a brand new pump or you getting your money back for a faulty pump. As you may be aware there's no equivalent serial number for your machine. A Japanese Operation and Maintenance Manual might be available and should cover changing the hydraulic oil, which should state the procedure for bleeding the pump. Process is the same for installing a new pump. Documents for your 7DK serial number prefix are discussed HERE . On a 6GK prefixed machine ('somewhat' similar to yours) the procedure is as follows: