Originally Posted By: fpracha
We do not have manual handling of the hydraulic oils because of mobile OEM system used to change the system fills. Each fill is approx 10 Ltrs to 20 Ltrs.
We are considering to use Skydrol due to its long oil life, stable natural viscosity range, and Skydrol oil's stability at temperature extremes of cold to warm to hot at high rotation speeds. Want to replace the spindle oil iso-10 grade with Skydrol LD4 or 500B-4. The hydrocarbon types have low life and thin out much at high speeds, losing film protection.
Your reasons all seem valid.
Originally Posted By: fpracha
Which once would you recommend ?
Aha, nothing like the hot seat ...
I'm reasonably well qualified to make a recommendation on machinery types with which I work, industrial and mobile hydraulics ... but this is out of my expertise. I must assume you've been using what the OEM recommends and it is not performing as you wish. The two things I would do are to contact the OE for their recommendations of a BETTER fluid in your operation than their usual, and to contact several synthetic fluid manufacturers for their recommendations. To get a decent answer will require product details you may not want to disclose here. Four companies who offer synthetic fluids are E F Houghton, Monsanto, Quaker, and Stauffer ... and I'm not suggesting those are the only ones, or even the best. Your viscosity alone puts you out of the range of what I play with ... 98+% of mine is ISO32-ISO68.
I cannot emphasize enough the importance of knowing what seal and line (if any flexible lines are used) materials are present, and what optional ones are available. I've not personally experienced it, but associates tell me that walking through a Skydrol spill dissolves your shoe soles. The owners of the one test cell application I worked on with Skydrol required full synthetic rubber suits and sealed goggles just to be in the room with it.
With phosphate ester fluids, your leak and disposal issues are greater than with petroleum fluids.
From MY experience, 5606 is closest to meeting your needs, but not ideal as you note.
Do report back on your results and what you learn.