my newly acquired Case 1840 states to use 10w30 oil in the hydraulic system. Do other brands also use 10w30 or do some use other things. Does it hurt to mix them? I just bought a used grapple, I think it was used on a Bobcat. I’m wondering if I need to purge the existing oil out of the cylinders and lines prior to hooking it up to my loader?
I would flush it out. You don't know what might be in there. Oil is cheap compared to anything else on a machine.
Ditto what Tom said.. Flush that puppy... We got away from renting hydraulic powered attachments/ hammers unless it went out with our machine due to contamination. Odds a slim but 3 minutes of your time beats the alternative.