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Discussion Starter #1
Yesterday I set out to change my front brakes. (2006 Road Star 1700 Silverado) When I got to the point of bleeding the lines, I was never able to get enough pressure built up in the master cylinder so that my lever would grab. What the hec?? What am I doing wrong? Also, the black weird little gasket that is in the MC looked all mangled....like it had been exposed to the wrong kind of fluid. I've had the bike about 3 years, just put fluid in not too long ago and everything was fine then. I am wondering, what are the symptoms of a failed Master cylinder?
 

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Discussion Starter #3
Well, that's a first, but I'm game. I'll give it a whirl. I would really like to know why it mangled in the first place. Some mysteries are never solved.
 

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Discussion Starter #5
Thanks Nick for getting back to me. I'm just sweating it. I'm hoping that it's not a failed master cylinder. I I have a friend who was telling me that he looks up two lines to the valves at both CalPERS and just let fluid run out of it and then he knows that the air is completely out of the lines which is also an alternative I suppose. I didn't expect a 30 minute job to become so convoluted.
 

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make sure you're opening/closing the banjo bolt in the correct sequence with squeezing the brake lever. i just have one caliper on mine so it may not be the same as yours, but i recently changed out my front brake and couldn't get any pressure built up until i figured out i was doing the incorrect sequencing.

for a single caliper, you have to pump the brake lever a few times, squeeze the lever and hold, open then immediately close the banjo screw/bolt, then release the brake lever. and do this over and over until pressure builds up. the sequence may be different for dual calipers so get someone to confirm which is correct for your bike, or just try a different sequence until you get it right.
 

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Discussion Starter #7
OK, seems to be getting worse. My brake fluid just turn to Jell-O. What say you I'm thinking master cylinder rebuild
 

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That part about your fluid looking like jell-o is a bit troubling. Sure you are using dot-4? On my duel calipers, I bleed one at a time till fluid runs clear, (adding fresh fluid the whole time) follow procedure bevo said, one or two it works the same. (Not sure what a banjo bolt is, I assume( I know, I know NEVER ASSUME!) he means the bleed screw/bolt.
 

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Really old brake fluid, contaminated fluid, or broken down fluid can gel. Sometimes stored open containers of fluid can gel if they've absorbed enough water. Silicone will attack brake fluid, too. Is it possible your "weird little black gasket" is actually silicone? Flush it all out and get new gaskets sounds like a good start.

Sugar Bear: the banjo bolt is the ring and bolt at the end of the brake line that connects the brake line to either end. The bolt is hollow and the fluid passes through it. That's different from the bleed screw which is similar in appearance to a Zerk fitting.
 

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I had a hard time getting the air out of my lines until I used the reverse brake bleed method with a syringe and filled the lines from the bleed bolt upward. Worked perfect and no pumping required. I got the syringe from a feed and seed store, one that is used for horses.


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Loupgarou
 

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Sugar Bear: the banjo bolt is the ring and bolt at the end of the brake line that connects the brake line to either end. The bolt is hollow and the fluid passes through it. That's different from the bleed screw which is similar in appearance to a Zerk fitting.
oK, Guess i am a bit dense here, but why not bleed with the bleed screw, the way I have forever done it? What am I missing here? I put a tube on the bleed screw into a container with my box end wrench already on and bleed away. (do not mean to jack no thread, just wondered:) )
 

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Discussion Starter #13 (Edited)
The fluid was contaminated. When I drained it out, it actually separated like vinegar and oil and thick. Still couldn't get the brakes to grab, so I bought a rebuild kit for the MC and now, just now, 2 days later, things are looking up. I think that weird little black gasket is OEM, but it needs to be replaced and that will happen tomorrow.

I bought this bike just by happenstance from the dealer when a guy dropped it off just the day before as it was exactly what I had been looking for. I am reasonably certain that the guy that had it never replaced the fluid and doubted if the dealer did either. Isn't it supposed to be changed every couple of years?

Thanks to all of you for the rapid responses, I truly appreciate them.
 

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oK, Guess i am a bit dense here, but why not bleed with the bleed screw, the way I have forever done it? What am I missing here? I put a tube on the bleed screw into a container with my box end wrench already on and bleed away. (do not mean to jack no thread, just wondered:) )
The master cylinder on many bikes including the Stars do not have a bleed screw. Only the calipers. But, even so, it's still completely unnecessary to loosen them to bleed the lines. I prefer speed bleeders. They make short work of the job. I'll reverse bleed if necessary, but not for normal flushing.
 

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You didn't attempt to upgrade to DOT 5 fluid, did you? It's purple, silicone based and doesn't mix with solvent based fluids. It makes JELLO.
 

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Discussion Starter #17
No Dot 5. Didn't even know there was such a thing.

You guys have all been wonderful, have given so much information. Can't tell you how much it's appreciated.
 
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