Just purchased an Hitachi EX 300 LC-3 and was wanting to change hydralic oil to Ecoterra Hydraulic Fluid HVI 46 or equivalent zinc free. Not knowing what was previously used in machine how much of the old oil needs to come out? I will drain tank completely but would be better to get remaining oil out of cylinders as well. How is the best way to go about this ? If the old oil does not come out what happens when the 2 mix. After reading some posts on here doesnt sound good mixing them. Thanks for any help !
Best way to figure out what you have right now is take a sample and have it analyzed for zinc. If it has zinc-free oil right now zinc should be less than 20ppm. That being the case you could probably get away with just draining the tank unless the ISO Cleanliness Code is way out of whack, say above 20/17. If zinc is around 1000ppm you have a typical normal hydraulic oil in the system and your problem just got way bigger.
Thanks Nige...I will get a sample next week. Im fearing the worst case though. If so.. I could disconnect one end of each cylinder; Boom,crowd and bucket and cycle a full stroke to drain whats inside them. There would still be contaminated oil in lines coming to them though. Just curious how would a guy clean or drain the swing and travel motors ? Another idea, though it may be out there, is to find some way to disconnect return hose coming into tank and cycle new oil from tank while returning "old"oil to another reservoir. This would be wasteful not knowing how much to run through system before assuming its clean though. By the way... hats off to you in taking time to reply to all these post. Im sure that can keep you very busy. I for one and im sure many more are greatful for your time ! :drinkup