deere 4500 Brake "chatter" problem? or not?

[Texwing]

Hi, I just bought a jd 4500 2wd, 460 FEL, from a local city at auction, a 2000 model, hours unknown. All is good except for a brake maybe problem. When i use the brakes lightly at low speeds, they seem to operate smoothly until the tractor is almost stopped, and then i get a chatter or noise from the brake area.
On pavement, from high speed to a fairly rapid stop, they are very smooth with no chatter or noise. It seems to be on low speed gentle stops. When the brakes on these series are bad, what are the symptoms? I don't want to tear into the brakes without a good reason, but don't want to tear anything up, either.
thanks for any help.

 

[Texwing]

Ok, I found the problem, accidentally-It was water in the tranny fluid. It came out looking exactly like coffee with creamer, light brown. New JD fluid, the low viscosity stuff, and the brake chatter has almost fully disappeared. I knew this tractor spent lots of time outside ( no more ) but did not figure on this. And the fluid did not look bad on the stick, the point being that its hard to tell the condition of the fluid on the stick.

 

[DennisFolsom]

Good to see your problem is resolved. My 4600 HST may have similar brakes to yours, but they work OK. Mine spends most of its time indoors, and did with the prior owner as well.

 

[Texwing]

Well, brake problem not yet resolved, but changing the fluid and getting the water out cured about 80% of it-I still get this chatter/ noise right before the tractor fully stops. Brakes are very smooth throughout their range except right before fully stopping, thats when i can get this chatter. I did notice that both brake actuation rods appear to have bends in them, but i can't tell whether its a factory bend or not. Parts book shows no bends.