Tractor Repair: JD 855 Brakes Squeal, brakes squeal, correct oil

Question
Both brakes on my JD 855 squeal loudly and high-pitched. These are wet brakes. I just bought this tractor, so don't have any history. Could it be the wrong hydraulic fluid?

Answer
Hello,

  The wrong type of fluid can definitely make wet brakes chatter or squeal.  Sometimes people use some type of universal hydraulic oil from a farm supply store because it's cheaper than the correct oil from the dealer, but not all oils are the same as far as additives.  Without knowing the history of the machine, there's no way of knowing what oil is in it, or the condition of the brakes themselves.  You may want to change the oil and put in JD oil and see what happens.