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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: AtLarge on July 19, 2025, 11:23:46 PM
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I was parking my bike after a short group ride and had a weird lockup. Somehow it mysteriously released luckily. Afterwards the thought occurred to me that maybe I activated a hill or parking brake type of action. Don’t see mention of it in the owners manual so, a quick google search says it’s a separate lever? I don’t have anything like that. How could I have caused it?
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AI overview is frequently inaccurate and not to be completely trusted without verification from other sources.
Until then, what could have happened—among other mysterious and perhaps karmic-related events—was the tiny return port in either the front or rear master cylinder could have been clogged temporarily by water or schmutz thus interferring with the action of one of the brake pistons. It could be a sign to do a thorough flushing of the front and rear brake systems.
Or perhaps AI just chose to screw with you, to wit:
(https://motobrick.com/gallery/4/1601-200725115437.png)
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My K1100RS came with a parking brake.
(The front brake lever would stick if pulled all of the way in so it had to be pushed out. It was handy at stop lights on hills. I did fix it though by taking it off and lubing it.)
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I can’t believe Mr Google lied to me after we’ve been friends for so long. 177381
:laughing4-giggles:
Thanks for the input guys. I will do some cleaning and lubricating. 112350
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Another item to investigate, how old are your brake lines..... If they are original you could be at the beginning stages of the rubber interior starting to fail. When it gets extreme it can act line a check valve and lock up the brakes.
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Good point Scott. They were replaced with braided at some point in time. I did flush and replace the fluid last year so, breaking down or contamination could be an issue.
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Which brake locked up, front or rear?
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Well, I really don’t know. We stopped for lunch and I pulled a mini U so I could back up into the curb. After I stopped I couldn’t roll backwards. One of the guys saw me struggling and grabbed the back to pull me. He couldn’t budge it either. After me flailing with the brake pedal and brake lever it let loose. It happened so quick I really don’t know why it let go. It felt like the rear though because I think the front wheel would have skidded from us pulling on it.
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Have you flushed the hose from the reservoir to the rear master cylinder to see if there is anything in it that could plug up the master cylinder? Run some brake fluid through it into a paint filter to see what may be in there.
If there is crap in the hose then it is likely that there is some in the master cylinder and I know of no way to clean it out. Fortunately, you can replace it with a cheap Chicom master cylinder for about 20 bucks.
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A mate had a similar problem it turned out that the rear brake lever was seizing up occassionally. Once removed and lubricated and adjusted the problem was solved..
Regards Martin.