Noisy pads when not braking!

[seismic22]

Hi,

Recently picked up a CBR954 and have noticed I can hear the pads making a constant ziizzzzzzzz noise when riding along. Its quiet loud and only gets drowned out at decent speed.
Ive lifted the front end and spun the wheel and it spins maybe 2 or 3 times before coming to a stop. Doesnt feel like disc is binding when wheeling it around etc

Any ideas anyone? Swear blind my last blade didnt make this noise. Fluid is fresh and master is full but not overfull. Bike seems to pull up ok but not like my 990 superduke did...

Cheers

[Cylon2007]

EBC sintered pads are well known for making this kind of noise, also because the discs are drilled this can also make them noisier. If they aren't binding and work OK I'd not worry about it.

[seismic22]

I meant to post the youtube link below to me spinning the wheel in the garage:

https://youtu.be/gvg09Lbtd-E

Ok thankss, yes i knew EBC HH's were noisy and i could here them a little bit on my old VFR when riding but these are particularly loud!

[seismic22]

OK, thanks. Never had a bike where pads are noisy when not using the brakes but will just have to accept it as it is!

Cheers

[CaptainSlow]

That's a fair amount of drag, I wouldn't be happy with that.

Take off the calipers and give the pistons a clean, push them out a bit to expose the scum line. Also, change the pins for stainless ones at the same time (put some copper slip on the threads to stop any galvanic corrosion occurring).

[gavgavgav]

CaptainSlow said:

That's a fair amount of drag, I wouldn't be happy with that.

Take off the calipers and give the pistons a clean, push them out a bit to expose the scum line. Also, change the pins for stainless ones at the same time (put some copper slip on the threads to stop any galvanic corrosion occurring).

I agree, thats not normal.

[seismic22]

Pads are not new. OK. maybe I'll whip them off tomorrow morning and give them a clean, any advice for cleaning the piston if there's any corrosion to the outer area? 1200 grit or similar? If I pull the pistons will they be easy enough to get back in using the original seals? Not actually changed seals in a caliper before and I need the bike next week so cant see myself being able to get hold of seals in time.

Edited by seismic22 on Friday 23 August 11:16

[CaptainSlow]

I wouldn't pop the pistons out fully, just a little bit to aid cleaning. I have a bit of skirting board off-cut that I use to put between the pistons to they all pump out evenly.

[mickrick]

They’re binding! Use scotch pad to clean the pistons, rotate it around the piston.

[seismic22]

Ok so everything cleaned properly and all back together and it was borderline worse than before, can only get a single revoltion of the wheel if spun by hand hard. Lifted the Mrs MT07 front end and can easily get multiple revolutions with the lightest of spins.

When un mounted I can easily push all the pistons back half way by hand and then with a bit of leverage help they push back in easily after that so not sure whats occurring. Ive now whipped the calipers off, split one of them and pulled the pistons...........all looks fine!!!

Soooo hunting for what else could be up...and wondering whether I could have done anything wrong when recently swapping discs and braided HEL lines off my old fireblade onto this one?? really cant imagine the discs could be affecting things but what about the lines? The lines bleed up just fine.

Any help appreciated particularly seeing as im meant to be heading to the pyrenees on the thing on Friday!!

[Rubin215]

The pistons should push all the way home with just firm pressure and should not need levered.

When you had the calipers split, did you remove the seals and clean the seal beds?

Over time, they fill up with crud or, if the last time they were rebuilt, the seals were lubricated with brake fluid, the brake fluid creates a crust that will push the seals out ever so slightly and drag the pistons.

You need to clean the seal beds properly and lubricate the seals with a minuscule amount of silicon grease or red rubber grease.

If you're careful when you're taking them out you can re use the old seals but, for all that they cost, you are as well to just buy new ones.

[smcapstick]

If your pistons push in readily and smoothly, make sure your pins slide freely and the pads can ‘float’ - they must not be tight in the callipers.

[seismic22]

Thanks both.

I have just finished removing all the seals. Of the 16 seals accross the two calipers, just two upper seals exhibited crud in the seal seat which i have now cleaned out. All lower seals have now been reinstalled. Uppers can wait to be reinstalled until tomorrow. Pistons do exhibit very limited pitting and i have flatted back the minor corrossion with 1200 grit. Pad sliding pins had already been cleaned up but will.make sure all are ok before reinstalling tomorrow.

I guess long term any pistons with even the most minor of pitting need replacing but if this current rebuild can get me to the ferry Friday and do a week euro tour with effective and safe brakes then ill be satisfied short term...

[seismic22]

Good thinking...i didnt initially swap the pads from the old bike but after a second thought i decided to swap them over aswell so as to avoid the need to bed them in like you say...so in summary yesterday the bike was running on the swapped discs, swapped pads and swapped lines. Thanks.

Update on rebuild is that whilst all pistons exhibit minor pitting all pitting is well above the piston seal. Putting it all back together right now.

[seismic22]

All back together and been for a spirited ride. Back home and up in the stand, its now spinning approximately 2 full revolutions by hand. Whether this is correct or not full a 4 pot per caliper set up i do not know! Bike rides fine.

[flexcreator]

For a quick check, go for a ride 1/2 mile + without using the front brakes. Come to a halt using the back brake only.

Jump off and feel both discs - cool is good, warm = brakes dragging, probably cured by a piston cleanup, Hot = brakes are binding, sort immediately.