[xcessiv]

hey guys, i just did a brake job and forks and all and now everything is awesome EXCEPT my brakes are rubbing the rotor some. not like in 1 or 2 areas, but the whole way around. i did NOT change the level of fluid in the system. i just pressed the pistons in to get the new pads in and give it enough clearance to get over the rotor. any ideas on what it might be?

the only thing i can think of is that when i cleaned the pistons, they arent lubed enough now to slide back in.

 

[Harp]

They're supposed to rub. If you can spin the front tire, it should spin between one and two turns before stopping -- due to the brake pads dragging on the rotors.

 

[Zeus30]

as long as they are not "grabbing" you should be fine.

 

[shiftn3rdon1]

its normal

 

[xcessiv]

guys, thats what i meant, like its ABnormal rubbing. in nuetral its more difficult to move it while on it, and like on an inclined road, in NUETRAL, i do NOT roll back!

EDIT: if i do spin it, i have to throw kinda hard to get 75% around. a normal throw it goes almost half way.

 

[shiftn3rdon1]

Oh that can't be normal!! I dont know, yeah maybe your piston is getting stuck or something. I never lubed my pistons before though...

 

[xcessiv]

crap haha ANYone else!!! ! !

 

[jener8tionx]

On my truck, depending on the pads I get, I have to wear them in a bit...100 mi or so, before they stop rubbing. My guess is the problem will go away as the brake pads seat themselves. Flame if I'm a Moe-Ron

 

[BroChaos]

just out of curiousity...why do the pads normally rub a little? kinda worries me when i'm going slow...i didn't know it was normal.

 

[jordanf600]

sounds like you tightened your axel too much. try to loosen it and spin the front tire, should be better. I keep my front axel bolt pretty loose but I safety wire it.

 

[xcessiv]

I FIGURED IT OUT!!! (btw i always torque to the cbr manual specs)

ok about 4000-5000 mi before the brake change, i added more brake fluid . well since the pads were much lower at that point, adding the oil made the system "perfect". but with the new thicker pads, the pistons are farther in and so there is too much pressure in the lines/ reservoir, so it forced the piston back out and in too great of a contact with the rotor.

and broChaos, the reason it scrapes in some parts a little (in the front) is because the rotor typically not perfectly straight, at least a slight amount of warping has occured, or the rotor isnt mounted perfect with the wheel. a lot of reasons. for the back its because one pad sit in close contact with the rotor and the other is moved by the one piston.

 

[quasi888]

just out of curiousity...why do the pads normally rub a little? kinda worries me when i'm going slow...i didn't know it was normal.

In a hydraulic brake system (even in your car) pads are always slightly in contact with the rotors. If it weren't so, you would be using up some of your brake lever's travel to move the pads to the rotors every time you brake -- not a good thing from a braking efficiency point of view. (Have you ever noticed how much you have to pump a brake lever/pedal after changing brake pads on a car or motorcycle? You're using all that travel to get the new pads in contact with the rotors again.)

It's the job of the piston seals to slightly retract the pistons whenever you let off on the brakes -- just enough to remove pressure on the rotors. They'll still drag a bit, but not in any consequential way once you're in motion.

 

[BroChaos]

thanks for the explanation!

 

[Visitor Q]

No worries, mine do the same thing and the dealer was the last to touch it in that area... How dirty!

Jason