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.
There is a specific air purge procedure that should be performed after pump service. Serial number would be helpful. File sent to you.
when all the oil from the tank has been drained or after installing the main pump it is important to ensure that the pumps case is filled with oil before starting the machine and any trapped air is purged from the pumps intake port through to the discharge ports. There is a possibility that the pumps can sustain some damage if these steps are not done prior to running the pump.
I made sure to put hydraulic fluid into the case drain hose before starting the machine, I only started the machine for a couple seconds each time on low idle. I bought more fluid to make sure I have enough, I will try the air purge procedure tomorrow. The serial number is: CJC02905
Do the air purge procedure first but if that doesn't help, re-check your work because it sounds like the pump is sucking in air.
Update I did the air purge procedure a couple of times and it still is making the noise. I checked the hoses I loosened before and they all are tight. I also poured hydraulic fluid down the case drain hose and loosened the fitting (circled in the picture) and fluid was coming out. Any other ideas?
Did you re-check the plate you put the o-ring on?
I made sure to tighten everything up when I put it on. And It’s not leaking like it was before, so I don’t think that’s the problem. The small o-ring that was causing it to leak looked like the letter C, with an eighth of it gone. It’s quite a bit of work to take it off. I’m trying to decide whether I should just have cat come out and fix it. There are a couple of agricultural dealers near me but I don’t think they’d be able to help.
what was the block that you removed to do the oring? , can you point this out on your pic of the pump.
I think it was the port block. If so hopefully the end plates and rotating groups got properly aligned. I’ve never attempted to assemble one horizontally
if you had the port block off and the port plates removed then recheck that you have not swapped the port plates over or rotated them by accident as this can be done and the pump will still work but there will be a lot of cavitation occurring. the port plates have a specific orientation even though they look almost identical.
I will check my work, take the port block back off, and check the port plates. There is a good chance that is the problem. Does anyone have a service procedure that shows the correct orientation for the port plates? If not, I'll just stop by cat and have them send me it over email.
I couldn't find a clear picture online of the ports plates side by side but hopefully this attachment I put together might help.
Thank you for the picture. If the plates were installed incorrectly, would they have gotten damaged?
They should be ok, they might be a little burnt but you should be able to clean them up ok. You can lap them back into the cylinder block by hand if need be, same process as lapping valve seats in a cylinder block by hand but you will want a fine paste between 1200-2000 grit.
When you changed oil did you clean the suction strainer in the tank?
I did not clean the suction strainer, should I have?
The strainer is supposed to be cleaned every time the oil is changed.