Brake issues

[akapellen17]

So I put on a cbr929rr caliper today with a mounting bracket and there is a buzzing/rattle when I apply the brakes? Is it the metal pieces behind the brake pad that are doing that? Thanks

[GS500Schultz]

Buzzing and rattling? Are the shims loose? Or pads loose?  Also did you allow time for the pads to bead in?


Also do you have a pic of the metal piece behind the pads?

Took me a few days for the new pads to conform to the rotor.  But no rattling just a slight vibration when I applied the brakes now its as smooth as butter

[akapellen17]

They are brand new pads. It's not really a rattle but a buzzing kind of sound. There is a metal backing plate behind the pad. Otherwise I am going to try to lightly sand the surface of the disc to make a new surface for the pads. Also, visually, I can only see the two Pistons on one of this sides moving, but not on the other

[GS500Schultz]

They are brand new pads. It's not really a rattle but a buzzing kind of sound. There is a metal backing plate behind the pad. Otherwise I am going to try to lightly sand the surface of the disc to make a new surface for the pads. Also, visually, I can only see the two Pistons on one of this sides moving, but not on the other

all 4 pistons should move. Sounds like it may need a rebuild as 1 pad isn't being pushed against the rotor.
or check the O-ring that goes in between the caliper as it splits apart. Those sometimes slip when reassembling and get caught in the passage. 

Also make sure you flushed the entire brake system. If you have the pneumatic bleeder it makes life about 100% easier.

[akapellen17]

Yea it sounds like it to me. I just don't have time to rebuild it since I'm leaving on friday

[akapellen17]

I'm still going to rebuild it, but any idea what the buzzing is?

[GS500Schultz]

the buzzing simply might be the fact that 1 pad isn't fully contacting the rotor.
making it vibrate a bit.

just make sure you bead the pads in correctly as well after you get the caliper rebuilt and bench tested.

[akapellen17]

How do you go about bench testing it???

[GS500Schultz]

How do you go about bench testing it???

one of two ways.

before bolting it onto your bike hook up the brake line and bleed it.
Put something between the brake pads so the pistons don't clamp all the way down. And pump the brakes to make sure all 4 pistons move.

or option 2, hook up a compressor to the bleeder screw and blow air into it while covering the banjo bolt hole. All 4 pistons should move.
but remember to put something between the brake pads so the pistons don't clamp all the way down.