low speed-Rear Brake-Rotational Groaning Sound-Now with Pics

[Tempest]

Just wondered what your views were on this..........

Some time ago, but, in "miles" not THAT many miles ago, I decided I should deal with my rear brake pads.... Getting a bit on the low side (but still worked fine)

The disc itself, as discs do, had various ridges on it, as they get over time, and a fair lip on the edge. Naturally some minty fresh pads would be up against an uneven surface, which would not be ideal.
I checked with the official Honda manuals, and measured the disc with a micrometer, and the disc still was fine thickness wise, even at it's thinnest point.

So long story, short. The disk was very accurately reground, dead flat or a rotary surface grinder. All lovely and flat, and still within the official tolerance of disc thickness.

The disc was carefully refitted to the read wheel, new pads purchased, replaces, and all bolts re-torqued

Ever since then, at very low speeds, and I mean, anything less than, say a jogging speed, there is like a groaning/graunching sound coming from the pads/disc.
Going quicker this goes away, and it has no effect on braking.
I had the pads out, checked them, and all seems fine. I can't see any issue, other than this noise, in time with the wheel rotation.

I'm assuming it's simply the disc to wheel join is fractionally out, meaning a tiny weave? as the disc rotates, and the read pad (one is static, the other moves) is having a pad to metal contact and sort of sending a vibration/friction sound thru the metalwork of the bike and making this sound.

Any thoughts on this one? anyone else ever have this?

It seems to have no ill effects, other than hearing it.

If I apply the rear brake slightly the sound seems to go.

[fabiostar]

take your pads out. and on the leading and trailing edge of them file a good 45 degree on them. some times certain pads can, buzz, as it where and can make a sound like your describing. iv had a few do it.

[Tempest]

take your pads out. and on the leading and trailing edge of them file a good 45 degree on them. some times certain pads can, buzz, as it where and can make a sound like your describing. iv had a few do it.

Thanks for the suggestion, will try that,

I'm sure when this 1st happened I took it apart and rechecked everything, just to be 100% sure all was correct, so was just hoping it would stop doing this noise, but either it won't or it's just not worn enough yet to bed-in.
I'll do as you suggest and hopefully it will work. The pads still look brand new, and have very crisp edges.
Great idea

[Tempest]

Ok, well I've just taken the rear pads out and taken a couple of photo's just to get opinions here, before I carry on.

The pads are: Ferodo Platinum FDB754P
As shown here: http://www.ghostbikes.com/3614-ferodo-p ... -pads.html

Purchased and fitted a few years ago, but in reality have only a couple hundred miles on them due to lack of bike use.
And from memory, this weird noise issue has always been there since I fitted them (and my reground disc)

Anyway, here are the photo's of the pads, just removed from my bike:






Those are "all the bits"

I am going to file the sharp edges of the pads away as you suggested.

Also, what about some Copper Grease/Copper Slip?
Should I get some (I had some, but need to search or buy new) and if so, what areas (on my photo's) should this be put on/over?

Thanks

[Wicky]

Check all the bits caliper components are in place & correctly fitted - esp. the retainer clips (part 4 & 6). Also that the pins (12 & 13) allow the caliper to move smoothly and aren't corroded and seized.

http://www.bike-parts-honda.com/pieces- ... STORM.html

[TheGingerBeardMan]

(editied, cos of what wicky posted, the same time as me writing this...)

With the noise occurring on rotation, and with it being a groaning/graunching noise, have you checked that the wheels bearings are not b*ggered?

I know you say that the sound is appears to be coming from the disc area, but, if riding the bike, the sound will be behind you, and it will be very difficult to pin-point where it's locating from. Is it 100% from the disc? And not the bearing directly in the middle of it?

Put a bit of A4 paper between pad and disc (one side at a time), and freely rotate the wheel. You will "drag" on the paper in places if the disc is out (higher than other places, if reground a few thou out)

Or, put the bike up on a stand, with the back wheel well off the ground and secure...then knock the bike into 1st gear and let the wheel spin/drive with no load. Then, you can have a listen right beside it.

With wheel NOT moving (and ignition off!), grab wheel and pull side to side....put it in gear (ignition off) and check for cush drive play and/or wear, that might make the rear wheel run a bit "off".

All rear sprocket nuts tight?

Caliper bolts not worn, and no play in the caliper? Has the rear caliper been slotted back into the "slot" on the swing arm?

[Tempest]

Check all the bits caliper components are in place & correctly fitted - esp. the retainer clips (part 4 & 6). Also that the pins (12 & 13) allow the caliper to move smoothly and aren't corroded and seized.

http://www.bike-parts-honda.com/pieces- ... STORM.html

Thanks.

Yes, those springs (lucky for me) are in place, and seem happy to stay there and not "PING" out!

Parts 15, 16 and 9 are the only ones I've removed.

Part 13 is done up VERY tight in the caliper and the smooth part of this pin 13, does slide very easy (with grease) in the hole.
I'll go and check part 12 is actually there in the middle of the rubber!, but yes, it does all seem very free moving/floating.

I've just filed on 45' chamfers around both pads (was easier than I thought!)

In my photo, I assume those thin pads between the metal backing and the brake pad are some kind of heat pad?

Also, about the use of Copper Grease and where to put it?

Thanks for any other replies..... I really don't know why it's been making this sound, as you can spin the wheel on a paddock stand and then it seems ok.... weird

[TheGingerBeardMan]

I really don't know why it's been making this sound, as you can spin the wheel on a paddock stand and then it seems ok.... weird

Which makes me think it could be wheel bearings, as the bike doesn't make this sound when on a stand (the bike is not under load as the wheel isn't pushing up from the ground)

Fire it up on the stand, and gently apply rear brake when bike in gear and "free-spinning".

Coppa-Slip on mine is just applied to the back of the actual brake pads, and on the sliding pins (very sparingly).

The plasticky spacer, according to Honda UK, is for heat displacement, to slow down the heat transfer to the piston seals. Which is strange, cos there's a heat spacer on the non piston side! The metal plates are anti-rattle.

A little bit of Coppa_slip between the metal rattle plate and the plastic heat shim won't do miracles, but doesn't hurt. Other folk don't use Copper grease at all, and just run the brake pads and plates dry.

[Tempest]

Thanks....... TheGingerBeardMan

To be honest I cannot be sure.
As you say, it's hard to ride a bike and pinpoint the sound!

All I know is that I'm sure it did not make the sound with worn pads, and after the disc was ground nice and flat, with a ground finish (I did wonder if the finish being too good and not a turned/liney finish might be the cause?)

As for all being back in place, well I'm as sure as I can be. Back when this 1st happened, I had apart again, and double checked everything was where it should be, and it's all torqued up to correct levels.

The noise seems to happen as I just roll to a stop, lets guess at around 10mph down to zero.
Experimenting yesterday I think the sound stopped if I applied the rear brake.

On a paddock stand, spinning the wheel by hand I did not hear anything.
I think, whatever is doing it. it's vibrating thru the swing arm, and amplifying the sound, as I say, I pull away and pick up some speed, there is nothing.
It's just the coming to a stop where you hear it, and I think just pushing the bike along manually (but need to try more experiment)

Just annoying

[Tempest]

I really don't know why it's been making this sound, as you can spin the wheel on a paddock stand and then it seems ok.... weird

Which makes me think it could be wheel bearings, as the bike doesn't make this sound when on a stand (the bike is not under load)

Fire it up on the stand, and gently apply rear brake when bike in gear and "free-spinning""

Ok, when I get this all back together, if it's still making this noise I shall do that (carefully!) and report back.

Just after some copper grease advice, (how much and where) before I attempt a reassembly
Why I laid it all out for the photo so I could be advised what areas to do
I know this stuff helps things move and may avoid vibration due to dry contact areas

[TheGingerBeardMan]

Coppa-Slip on mine is just applied to the back of the actual brake pads, and on the sliding pins (very sparingly).

The plasticky spacer, according to Honda UK, is for heat displacement, to slow down the heat transfer to the piston seals. Which is strange, cos there's a heat spacer on the non piston side! The metal plates are anti-rattle.

A little bit of Coppa-slip between the metal rattle plate and the plastic heat shim won't do miracles, but doesn't hurt. Other folk don't use Copper grease at all, and just run the brake pads and plates dry.

So, for your pics, it's quite safe to cover all parts with a THIN film of copper grease - making sure NOTHING is left to run onto the pad itself (the edge of the pad should NOT have grease on it either!

The caliper pins and the caliper bolt that goes through the boot rubber can also have a thin layer of copper grease. Again, emphasise on the word "thin layer"

[Varastorm]

Those pictures of the pads look as if they have seen some extreme heat.

Are the pistons sized or tight?

What usually happens is over time you get a build up of condensation behind the brake piston seals, which then leads to corrosion that pushes the seal out onto the piston.

Then when the brakes are applied, the pistons come out & pressure from the pads is applied to the discs. But when you let go of the leaver the tight seals on the pistons will not let the pistons retract from the disc, causing similar problems to what you are experiencing.

What I do is make a "groove scraper".

Firstly, get hold of a welding rod & flatten the end. Then grind it so it looks similar to a small instrument screw driver tip. Then I bend the end 90° so that the flat runs with the wire & make a triangle with the excess so I can grip the wire comfortably.

Then, all I do is stick a cotton needle/pin 2mm in the side of the oil seal & drag it out of the groove to remove the seal.

Warning, if you don't "stick" the needles in properly, you run the risk of the needle coming out & damaging the seal edge & ruining the seal.

With the new home made groove scraper, slowly & carefully scrape the corrosion out of the groove.

Once all the crap has been removed, I clean with brake cleaner & wipe/air gun the grooves clean, then liberally coat the grooves & seals with new brake fluid & pop the seals & pistons back in

It will be as good now as when it came out of the factory

It is recommended to remove the caliper if tackling this job, so make sure you clamp the brake pipe to stop the oil from draining from the master cylinder. Last thing you want is air locks in the Master, they are a pain to sort out.

Good luck, you won't be sorry

[Tempest]

Thanks.

Ok re the copper grease instructions.

Re the pads, well, when fitted I did use a clamp and wood to push the single piston back to make room for the new pads.

Heat wise? Well you can rock it when it's all done up, so it's not like it's all locked tight, and as I said, the rear wheel will spin very freely by hand when on a paddock stand.
And this noise started when the pads were done, it's not a noise that gradually started over time as they glazed.


I did wonder if the surface finish on the discs could be too good? (if such a thing is possible?)

I'll re-assemble it (look for copper grease or buy fresh) and see if any difference. If the noise is still there, I will do the run bike on the stand and try the brake test, and go from there....

Will report back whatever I find

[MacV2]

If your doing the seals its RED RUBBER grease you need for the seals, thin smear & pop the seals back in.

When you push the pistons back in they need a smear of fresh brake fluid to lube up ...

[Tempest]

Thanks for the seals advice, though not planning on touching those


Ok, Time for a little update:

Had a brainwave, or rather a 'Lets do the obvious moment' and wheeled my bike around the driveway with the rear pads out and caliper taped out of the way, to see if there was any of this noise whatsoever at low rolling speed, as that's when I hear it also, when foot peddling around.

Nope, nothing, sheer bliss silence. So, there you are, nothing to do with front brakes or bearings on either wheel, so it's 100% certain the rear brake (pads)

However (this may be the key here)
I'm missing item 6 here:
http://www.bike-parts-honda.com/pieces- ... STORM.html

The rear of the pads were just sitting on the metal cut out of the caliper mount/holder, not in any little sprung bit, as far as I can say, that was not there, when I did the replacement. Perhaps this is why I was getting this noise?

Also can't find my dam Copper Grease so need to buy more

So, at least that's progress. It's nothing other than the brake, and I'm missing that rear spring clip (whatever it does)
So a few little purchases, put back together later next week when bits arrive? and see what happens....

Yes?