I’ve got a Cat 315cl that I replaced an o-ring on the block port that bolts onto the main Hydraulic pump (picture below). To do this I drained all the hydraulic oil in the hydraulic tank and when I went to fill the hydraulic tank I put the oil that was in there before and some new cat branded oil. After this the pump was cavitated and when I looked in the hydraulic tank there was white foam/bubbles on top. I also loosened one of the lines and white foam came out. I assumed that the old oil was different and so I drained all of the oil from the tank, cylinders, lines that go to the final drives, hydraulic pump, and as many hoses as I could. There was white foam in a couple of places that I drained. I bought some ISO 32 oil (not cat branded), which is the same as the Sae 10w oil the cat dealer gave me. I filled up the hydraulic tank using only the Iso 32 I bought while I had the case drain hose off. After I filled it up I turned the machine on for a few seconds and the noise was still there. What I want to know is how I can get rid of the cavitation.
Sorry for the long post.
![9B6E5499-3C2A-484A-AD0D-0B4C55A3C258.jpeg 9B6E5499-3C2A-484A-AD0D-0B4C55A3C258.jpeg](https://www.heavyequipmentforums.com/data/attachments/297/297250-502b5b3735070029dfe11688de4d90a6.jpg)
Sorry for the long post.
![9B6E5499-3C2A-484A-AD0D-0B4C55A3C258.jpeg 9B6E5499-3C2A-484A-AD0D-0B4C55A3C258.jpeg](https://www.heavyequipmentforums.com/data/attachments/297/297250-502b5b3735070029dfe11688de4d90a6.jpg)