"Squawk" is how I describe the sound the brakes make. If I step on them hard, they may even screech. Yes, they are noisy (I think especially when new), but they get a little quieter with use, or so it seems. By comparison, we don't often hear it, but some aircraft brakes squawk horribly too. I flew on a Westwind II a few years back and the noisy brakes were so loud I asked the Pilot about it. He said it was normal. After asking several mechanics the same thing and getting the same answer, I quit worrying about it. Airplanes have little to do with tractors, but everyone I have talked to says the wet-disc brakes are prone to being noisy. Hope this helps.
JimI