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Discussion Starter · #1 ·
I have a 99 r6 with some really bad brakes. I've tried everything to resolve the problem but to no avail. When I pull the lever, I get this weird crunching feeling. I bled the brakes and the crunching feeling went away for a little bit. It's back now, so I know I need to do something different. The bike has goodridge kevlar lines with brand new ebc hh pads and yet the bike still brakes horribly. What should I try now?
 

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Sounds like the pads might be glazed. Did you spill any chemicals on the pads when you were bleeding them? I know it's elementary, but I see it all the time in the shop. ARE YOU SURE THE PADS ARE ON OPPOSITE SIDES OF THE ROTOR? I see them stacked next to each other all the time and the metal brace does the braking and the actual caliper piston contacts the rotor.
 

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Discussion Starter · #3 ·
This problem occured before putting on the new pads. And I did make sure the pads were put in correctly, and I'm not braking real hard quite yet to break in the pads. I really think the problem is happening with the fluid or the master cylinder. What are signs of a bad master cylinder?
 

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Well a few things can happen to a master cylinder, most often, it will act like there is air in the line. Basically what happens is fluid moves past the piston in the master cylinder and back into the reservior. It will feel like there is air in the lines when there may or may not be. Less often, you will pull the brake lever and one of the ports in the cylinder will be blocked and cause the pistons to contact the rotor and stick there, they will not back off and the pressure is trapped in the line.

Are you sure the rotors aren't bent?
 

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Discussion Starter · #5 ·
Where is this crunching feeling coming from? My other bikes have a nice, typical feel in the lever.
 

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Ive never experienced a "Crunching" feeling before. Is it making noises? Pulsating? Is the lever spongy? What material are the EBC pads made of? Are your rotors stock? Are your rotors grooved, pitted, warped, scored? Im just trying to get more information.
 

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Discussion Starter · #7 ·
I just changed the fluid again with brand new fluid, and I think this might've worked. I think the fluid I first used was old and probably had some moisture in it. When I pull the lever you can actually see the lever sort of stumble. You can hear a noise, which sounds like a "crunch". I have the ebc hh compound pads and the rotors are completely stock. The rotors appear straight with no warping.
 

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Has the noise gone away since you changed the brake fluid? If not, try squirting a bit of lubricant on the lever where it's perched. Maybe it's just rubbing against it's perch? Even with water contamination, which I have seen quite often, Ive never experienced a crunching sound/feel. Let me know if the problem is solved. Im kinda in the dark with this one too.
 

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Discussion Starter · #9 ·
Great news, the problem is back. My description of the problem is pretty vague, but that crunching feeling remains. I put in yamaha dot 4 fluid, so I don't think the fluid is the problem. The crunching feeling went away completely as soon as I got done with the bleeding but then came back within an hour once pressure was built up fully. I also can hear a very distinct clicking noise when the lever is pulled in all the way along with the stumbling. I am thinking of getting a new master cylinder off ebay, since they only run about $20 sometimes.

I honestly think my rear brake does better than the front. Last track day, I had to use the rear brake all the time. I have a track day on thursday, and would like to fix the problem. Who knows.
 

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Jesus, your pads have to be glazed. Your fronts should flip the bike over end. Is there pressure when you pull the lever back? Or does it go all the way to the bar?
 

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Discussion Starter · #11 ·
There is pressure. It feels like a normal, working brake lever up until the last inch where the weird stumbling occurs. I just replaced the pads, and I haven't tested out the new pads. The old ones were worn down pretty good. I noticed that I only get about 6 inches of movement when I turn the front wheel. I should have more than that shouldn't I?
 

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Discussion Starter · #12 ·
With my calipers off, I cleaned off some brake dust off the pistons. I assemble everything back together, and the crunching feeling has gone away somewhat. I'm going to clean all the pistons now, so hopefully this is the problem. Is there anyway to clean the pistons without having to bleed the whole system again?
 

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No, in order to clean your pistons, you will have to disassemble the caliper. It's not difficult to bleed the lines, albeit it can be a pain in the ass. I would recommed that however. Perhaps your pistons are scored a bit, or something is off in your caliper. It's a long shot, but im having a hard time coming up with anything else.
 

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Discussion Starter · #14 ·
I might disassemble after my last track day. I'm afraid I'll really mess something up rendering my bike useless. I'll get this fix one way or another. Thanks for the help.
 
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