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Discussion Starter · #1 ·
I was having a problem with my brakes sticking up front, and thanks to the help of the members of this forum, that is fixed. Now I'm on to another problem. After bleeding and bleeding and bleeding and no air that I can see....I still have a soft lever. Well, then I started thinking and examining and thinking some more. It seems to me that the problem is not air at all. I think the problem may be that there is a visible space between my pads and the rotor. Not all the pads either. On each caliper, on one side at the top there is a visible space. When I squeeze the lever, as soon as that space is taken up, I have a firm lever. The problem is.....that space isn't taken up until I am almost to the grip. :(
So....does anyone have any ideas why I might be getting that little space on one side of each caliper like that?

Info:
1) 2001 GSXR 1000 forks / brakes, 2006 GSXR master cylinder
2) No warp in the rotors that I can detect
3) I'm 99% sure there is little to no air in the system

Thanks in advance for any help you can give!
 

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Is my bike ok?
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Suzuki just announced a massive recall on the front master on all gsxrs from the past decade or better. Might be your problem.
That doesn't explain the gap between the pads and the rotors,though. Seems like the pistons are retracting too far,but I don't know how that would be possible.
 

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Discussion Starter · #4 ·
Seems like the pistons are retracting too far,but I don't know how that would be possible.
Yeah, I'm puzzled too. I just can't wrap my head around a cause. The only thing I can think of is to order a new seal / o-ring kit for the calipers. Maybe if some seals are currently tighter, and some looser, then when the pressure is released when the lever is released....they are responding unequally to the release. That's all I can figure. That's going to be my next step if I can't figure anything else. :/
 

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escape from prison planet
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it was my understanding that the pad always rested slightly on the rotor, unlike a car that has a dust "boot" to slightly retract the piston. im trying to wrap my head around how this would happen. is it possible that there is a slight vacuum in the hydraulic system? i think someone outlined something to that effect in your other post. something about a seal covering something.
 

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lɐʇuǝɯᴉɹǝdx&#4
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Yeah, if you get firm contact once the pads engage, its not air in the line.

Is it maybe just that the pads are worn? Less pad = bigger gap. Although, the master should push fluid in behind the slave piston to take up the space... so maybe the problem is they are retracting to far, and fluid is getting pushed back into the resevoir? Perhaps there's a bad / mis-installed seal somewhere?

Does it only happen when the bike is moving, or is it the same when stationary? If only a problem when moving, there might be something other than rotor warp that makes the rotors wiggle in the calipers, like mis-aligned or worn bearings.

Not directly related, but I've got some hydraulic bicycle brakes that don't have a fluid resevoir. Instead there's a screw you turn in that forces a secondary plunger into the master cylinder, letting you set the pad clearance directly. When the (rubber, rim braking) pads start to wear, they have exactly the problem you describe, and you have to turn the screw in to advance the pads (then when you replace em, you back it out again). A resevoir does essentially the same thing, only automatically, by admitting a small amount of extra fluid to compensate for pad wear. So if it lets that fluid back out... well, it won't advance the pads, and you get to much pad clearance, even with fresh pads (because that's how pad clearance is set).

TLDR- your probably on track with checking your seals.
 

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Discussion Starter · #7 ·
Thanks for the input guys. I was trying to decide on ordering a new set of seals ($100) or picking up a used set of calipers (found a set with braided lines and a spare master for $125). I opted for the used calipers on the hopes that it will correct my problems. I know that the used set might have the same exact problem, but I'm crossing my fingers that I'll get lucky.
 

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Pump it up hard, put pressure on it to push the pads completely to the rotors. Any time I change pads and push the pistons into the caliper I'll have to pump the lever and put some decent pressure on it to really push the pads to the rotor. Unless theres just something catastrophically wrong with the brake system the pistons should not retract to the point of a gap in between the pads/rotors.

Anytime I bleed my brakes though there'll be some sponge, but not much; and it'll be gone by two or three rides. There'll often be a slight bit of air in the system and it'll work its way out by itself I find. a lot of people, after bleeding brakes, will leave the master cylinder bleeder cracked open a hair over night to let any air escape.
 

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You have those crappy Tokico 6-pots. Change them for any 4-pots that fit, ISTR there are some Nissins that will do the job. Usually one or more dust seals get dirt and corrosion behind, and the piston sticks. This will give your squishy feeling.

Nissin > Tokico, every time.
 
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Discussion Starter · #12 ·
Hey everyone, thanks for the ideas and suggestions. Just wanted to give an update. I replaced my calipers with the used set I picked up on Ebay....viola!....rock hard lever. I'm pretty sure that a caliper rebuild kit would have also solved the problem, but for 25 dollars more (100 rebuild kit, 125 used caliper), I figured I'd go that route just in case it was something else with the caliper that I cannot put my finger on. Either way, its solved and I'm riding.

Thanks again!
 
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