Rear brakes ghosting me during riding.

Information and questions on GL1100 Goldwings (1980-1983)
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Posts: 1
Joined: Thu Jun 02, 2022 12:25 pm
Location: Houston
Motorcycle: 1983 Goldwing

Rear brakes ghosting me during riding.

Post by BrokenBodyEngineer »

Hello all. I've been working on my 83 Gl1100A project bike. After about 1k miles of riding it since buying it, my rear brake pedal suddenly went dead. Thankfully I had already rebuilt the front brakes and master cylinder on day one an only was only about 15 miles from home so I was able to engine brake my way home. The rear brake went from almost no take up and great stopping power to completely dead, pushing the pedal down until it bottomed out against the frame with zero effect. I took this as an opportunity to rebuild the rear brake system, and rebuilt the rear caliper, master cylinder, and replaced the lines with braided steel. Problem solved right? Nope.

Starting out on my first test ride through about 5 stops and 10 miles, the rear brakes were great. Then, with no in-between function, the rear went dead again just like before. Going home, I test for air in the lines. The front brake had absolutely no air in the line. The rear brake had a lot, 2 or three bleeds worth. I can bleed the brakes until they are nice and tight, let the bike sit overnight and then in the morning they are dead again. Air in the rear caliper. I'm a pretty experienced mechainc but know nothing about bikes except what I've learned on the go. Brake systems are brake systems, somehow my sealed system isn't. I even swapped my rear caliper with a spare I grabbed off a donor bike and the issue still exists. There is no brake fluid weeping anywhere on any components. Am I missing something, or is time to swap in the latter model rear master? It looked fine when I was rebuilding it and there are no obvious signs of failure, am I missing something since the air is ONLY getting in the rear line?

Thanks for the help!

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Joined: Sat Jun 26, 2021 4:12 pm
Location: Richfield, Wiscsonsin
Motorcycle: 1983 GL1100 Aspencade
2007 Yamaha FZ1
1992 Yamaha FZR1000
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Re: Rear brakes ghosting me during riding.

Post by Sig45227 »

Oddly enough the same thing happened to me last week. I got to the End of the Street just to start my ride and zero brakes. Mind you I unlinked my brake system about a year and a half ago and everything have been functioning perfectly since then. I took the bike back home stripped off the bag on the left side and bled the caliper.
There was a ton of air in it, not sure how it got there. My Master's Reservoir was a little low so maybe it sucked air in? Seems improbable but that's what was going on. Seems to be keeping pedal pressure now hopefully it doesn't leave me stranded somewhere.
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