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Author Topic: 2008 GV650 - Rear brake problem  (Read 269 times)


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2008 GV650 - Rear brake problem
« on: April 20, 2017, 10:54:06 PM »

 Hello everyone thank you for having me I am a new member and have just signed up. I had just purchased a 2008 GV650 Aquila with 6250 KM.  When leaving the sellers driveway I was going downhill and went to apply brakes the rear brakes grabbed excessively hard but did not lock up. I was in traffic and had nowhere to go and forced to drive through with a dragging rear brake.  I had to drive approximately 3 km to get to an area I could park, by this point it got so hot it turned the rotor purple and melted the rubbers and seals causing excessive smoke. Once it cooled off I was able to retract the Pistons,  and checked the sliders all of which seem to be working properly since it cooled down. I had tried to bleed the brakes without success only to find out nothing was coming out of the master cylinder to the rear wheel. I removed the brake line outlet of the master cylinder  removed the master cylinder cover and no fluid would flow nor will it shoot out while applying the rear brake pedal. I assume the heat damaged the seals in the master cylinder. My main question is are these master cylinders,calipers & seals  sensitive to heat? Keep in mind this bike had sat for more than one and a half years without moving anywhere so a brake sticking on I can understand just not the sudden failure of a master cylinder.  I would also love to know a good source to get parts from since I am in Nova Scotia Canada I have no dealerships close to me. Thank you for any help you guys and gals may give me.

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Re: 2008 GV650 - Rear brake problem
« Reply #1 on: April 20, 2017, 11:59:48 PM »

What happens: the master doesn't spring back properly after you lift off the brake, and the pads drag a little. This creates heat. The disc expands, which creates more heat and more friction, the pad backing plates expand, the pistons expand, more heat, more friction, more heat...

They are known for it. It's mended with what's known locally as the Silver Pill Fix - forum search for that term - which is a spring, pushed into the master cylinder, so it draws back and scavenges correctly. I also highly recommend the Armstrong brand "wavy" rotor. Even after an episode similar to yours, with rotor glow and actual fire, the disc I have did not warp at all.

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