Rear brake squeal

[97Valk_CT_Euless]

Hello all.
Rebuilt the rear brake assembly front-back about 2 weeks ago.  Master cyl, hoses, lubed lever joints, rebuilt the caliper, new retainer springs and caliper bolts and boots (because i was there), new OEM pads and a new EBC rotor (which may be the problem).  Bled the heck out of it and after assembly was real careful on the rear brake for about 100 miles while it bedded in.  Now it stops like a dream, very smooth and as strong as I want it to be.  Very smooth, VERY strong.  Now, about 100 miles leter, I get a pretty annoying squeal when stopping, but only at very low speeds (like the final foot of stopping at a light).  I did NOT prep the disk surface (didn't see it in the instructions) but maybe I should have.  Like I said it was great after bed-in for about 100 miles before this started.  Still no problems with brake strength or control.  Still very smooth and strong.  Everything appears to still be in place.  Any ideas?

[old2soon]

This is NOT carved in stone but from what I understand-E B C pads with E B C rotors and O E M pads with O E M rotors. I've got O E M pads and O E M rotors all around. Even when the pads got thin there was NO squeal. It MIGHT be the combination of pad and rotor you have or it might NOT be. I know-not lotsa help forthcoming. Research it a little more here on the tech board and the answer MAY already be here.  RIDE SAFE.

[Ricky-D]

Evidently you cannot identify exactly which brake is doing the squealing so more diagnostics isn't practical nor enabled.

I'd say, you maybe still have a little air in the system, so bleeding might take care of your problem.

***

Evidently I can't read either!!! my bad.

I see it now - duh

[97Valk_CT_Euless]

I guess I wasn't clear, it's definately the rear brake squealing.  I'll try re-bleeding.

Thanks.

[sandy]

" new OEM pads and a new EBC rotor (which may be the problem). "

Oh yeah. I'd start with another new OEM rotor or go with EBC pads.

[F6MoRider]

Does it come and go?  Or is it constant?  Can you modify the squeal by pressing the brake pedal hard and releasing? 

Redid mine two years ago and would occasionally get a metal on metal grind briefly followed by a scraping type squeal when applying the rear brake but found I could kick the pedal and it would stop. Took it apart, didn't find anything, no abnormal wear, put it back together and the problem hasn't recurred.

[97Valk_CT_Euless]

F6- The way you describe it is exactly like I would.  Only makes noise at very low speed, a couple of MPH at the end of the stop.  Sometimes it's barely noticeable.  Sometimes it's a metallic (retainer springs singing?) almost grind.  Rotor doesn't appear to be getting "ground" in any way.  Yesterday, almost no noise at all during stops, then at one stop "wreeeek!".  Again though, absolutely no indication that braking action is suffering.  I'm going to bleed it and take it apart this weekend and see what I find.  If the pads look glazed, I'll scuff them and try again.  May just be incompatibility with the rotor or maybe I'll find something.  I didn't lube the back of the pads since I got the OEM's with what appear to be moinse damping backing plates.  I'll do that too.

Thanks to everyone for the ideas.

[Chrisj CMA]

Left rear wheel bearing going bad will make the same sound sometimes.

I suggest putting the bike up on a jack and grab the bottom of the rear wheel and try forcefully to move it side to side.  If you feel a tic tic sort of movement (very slight) more like a sound than a movement ........bad bearing

[Moonshot_1]

Left rear wheel bearing going bad will make the same sound sometimes.

I suggest putting the bike up on a jack and grab the bottom of the rear wheel and try forcefully to move it side to side.  If you feel a tic tic sort of movement (very slight) more like a sound than a movement ........bad bearing

2nd that motion. Reading this thread and had the same thought. Check the bearing. Couldn't hurt.
Sometimes you simply just don't hear it until you slow down and things quiet down then the pitch of the sound becomes audible and the engine and wheel noise subsides.

Had my brakes redone last year and chased down the similar noise. Seemed like the brakes. Just had'em done so that was the prime suspect. Was the bearing. And if the wheel is moving around just a little bit, the disk may be slightly rubbing the pads because of it and squealing when you get to slow speeds and when you apply the brake, the squeal goes away.

[97Valk_CT_Euless]

Absolutely will check the bearing.  Just replaced the tire and checked them then (same time as the brakes) but am really paranoid about it.  Lost the splines due to PO having the tire changed (and push/pulled) apparently no other service done.  Combination of bearing and lack of lube.. You know the sad spline story.  Replaced the bearing then but when I have the bike up I'll definately look at it.

Thanks again all.

[F6MoRider]

One other question for you.  Are you torquing the rear end to the spec or simply tightening the bolt until you think it's tight enough?  When I disassembled and reassembled mine the second time, I torqued it to the spec which I neglected to do the first time.  No more squeal, squeak, or grind and that's the only change I made.  Bearings squeal when misaligned, brakes do as well when torqued incorrectly and misaligned.  Just a thought.

[97Valk_CT_Euless]

Torqued to spec. Like I said, paranoid!