Rear Brake Rubbing

[Bonner]

I have just replaced the pads, brake lines fluid and cleaned out the calipers. The seals seemed pretty good (Clean, flexible no damage) so I just re-used them. The problem is that I now have a pulsing squeak in my rear brake. You can hear it at low speeds and the disk gets quite hot so it's definitely making contact with the pads.

What could be causing this? I've re-bled the system and there was a little air still in there (Which I removed). I'm dreading that it's going to be another warped disk, because it always seems to happen with bikes I own, even though I don't ride hard.

 

[motojoe122]

I have just replaced the pads, brake lines fluid and cleaned out the calipers. The seals seemed pretty good (Clean, flexible no damage) so I just re-used them. The problem is that I now have a pulsing squeak in my rear brake. You can hear it at low speeds and the disk gets quite hot so it's definitely making contact with the pads.

What could be causing this? I've re-bled the system and there was a little air still in there (Which I removed). I'm dreading that it's going to be another warped disk, because it always seems to happen with bikes I own, even though I don't ride hard.

Your rotors might be glazed a bit, you can try roughing them up some. I think there is a how to sticky for replacing pads.

 

[YZF73]

As you've said the noise is pulsating, it does sound as though the disc is warped to some degree.

Whilst spinning the wheel, watch the disc and try to estimate the amount of deflection (unless you happen to have a DTI handy :thumbup. The manual specifies a maximum deflection of 0.15mm, which you'd probably only just see by eye.


Hope this helps,

Yamahaboyz

 

[YZF73]

Any luck??

 

[TownsendsFJR1300]

+1 on the warped disc.

I suspect its warping as the pads are dragging due to old caliper seals hardening up and not releasing the piston.

Have you ever changed the seals out?

Yamaha recommends changing them EVERY TWO YEARS. I'm still on my original rear seals but the fronts were rebuilt at roughly 12,000 miles due to dragging..

Its a pretty easy procedure, especially the rear. Its a lot cheaper than replacing new pads/rotors often. Your mileage should go up too especially if that rotor is getting that hot when the brakes are NOT applied... That rotor should stay cool when not applied.

Even with a slightly warped rotor, new seals will allow the pads to retract as they should. You'll still have pulsating in the pedal but the rotor won't be hot and you won't be prematurly eating up your pads.


BTW, when I rebuilt the fronts, I felt/compared the new seals to the old seals, I could not tell ANY DIFFERENCE. Age/heat take a toll on the rubber seals, the seals will stick and not release the piston. The front wheel, when lifted off the ground (centerstand and sizzor jack under the header) now "free spins" by hand, 4.5 full turns vs before the rebuild, about 3/4 a turn... That was with about 5 years on the original seals, not two years...

IMO, new rotors/pads without fixing the real problem will have you chasing your tail and throwing your money away....

You also want to pull the two caliper mounting bolts. The caliper and two bolts tend to gum up if not serviced and will not allow the caliper to move when the pads wear with time. Clean the bolts, the holes they go into and re-grease (Use brake grease due to the heat and it won't fling out/drip). They make brake specific grease: ([ame="http://www.amazon.com/Permatex-24110-Caliper-Brush-Top-Bottle/dp/B000HBNV6W"]Permatex 24110 Ultra Disc Brake Caliper Lube, 8 oz. : Amazon.com : Automotive[/ame] ). They should move very freely. I just ahd to replace a rear tire and had previously cleaned and lubed those bolts/pin's. They were starting to get sticky and got serviced again. They now move nice and freely allowing the caliper to move as it should...

The rear seal kit, at least in the US is about $6.00 USD,

http://www.partzilla.com/parts/sear...4/FZ6+-+FZ600SS/REAR+BRAKE+CALIPER/parts.html

 

[greg]

fwiw mine still drags a little, and that was after i replaced and greased the seals. though it didn't get quite as hot

 

[TownsendsFJR1300]

fwiw mine still drags a little, and that was after i replaced and greased the seals. though it didn't get quite as hot

Did you clean and regrease the two main mounting bolts? They do gum up with time and tend to stick...

 

[greg]

Did you clean and regrease the two main mounting bolts? They do gum up with time and tend to stick...

i think so, i remember giving one a clean with some wire wool

 

[TownsendsFJR1300]

i think so, i remember giving one a clean with some wire wool

They need to lubed with brake specific grease too...

IE: [ame="http://www.amazon.com/Permatex-24110-Caliper-Brush-Top-Bottle/dp/B000HBNV6W"]Permatex 24110 Ultra Disc Brake Caliper Lube, 8 oz. : Amazon.com : Automotive[/ame]