82 KZ550 4 cylinder. I am finding trace amounts of what looks like brake fluid on the frame ahead of the rear tire. It'll sometimes be splattered on the exhaust in small amounts. The Kawasaki shop manual is so hard to understand I can't figure out what it is. There's what looks like a bleeder valve on the frame ahead of the rear tire. I can NOT figure out what it is. The rear brakes are drums. Any ideas would be appreciated.