You state you have deposits on the dics yet you are now saying there isn't any!
The disc in the picture is a make I don't recognise but the surface looks fine to me, obviously without clocking with a DTI I've got know idea as to whether it has excessive run out or not. Modifications to the pad spring is totally unnecessary and only done to hide a serious fault i.e. worn inner caliper bodies and/or cheap pads that are too small and that move excessively within the body causing accelerated wear. The calipers are designed by experts and work extremely well they don't require modifications to make the work, if they fail to work as they should something is WRONG!
Most cheaper and some quality pads are too small only by a few mm in some cases but enough to allow the pad to move excessively under braking. This wears the caliper body on the pad mating surfaces, which in turn makes the already over large tolerance between pad/body even bigger, EBC was really bad some years back one of the reasons I stopped fitting them.
Providing all the pistons are free within the calipers they will not will not cause brake judder. That said if any are semi seized or seized this will distort the disc/s and can give you judder, the same will apply if the centre rota has become bent. If your calipers have badly worn inner matting surfaces this to can cause judder by trapping the pad in the worn area/s and not allowing the whole pad surface to contact the disc.
If the pads you're taking out are tapered either top to bottom or end to end you have the above issue which could be caliper body or retaining pin wear and or semi seized or seized pistons.
There are also many fake products on the market all packaged as quality parts even stealers get caught out. Personally I wouldn't bother with after market discs unless they are from quality suppliers, often these days OEM is cheaper or only slightly more expensive. I recently replaced the disc on my GSXR due to pitting OEM was cheaper than EBC!!!!
As others have stated dics/pads aren't the only reason you get brake judder thoroughly check the head races, forks, wheel bearings, wheel spindle and cracked/bent frame. I would remove those disc check you OEM ones for wear and run out if ok refit, check the calipers for excessive body wear, semi seized or seized service/replace as required put in OEM pads that are square or fit SBS.
These calipers are the dogs boll%$ks but require attention to keep them that way deposits..........red herring!!!
Whenever i clean up the calipers i push them out further than needed for braking, then i can push the pots back in with my fingers, so in that respect i will say they're not seized.
I had pads out a couple of months ago and they looked as good as new, no lumps or chunks out of them, or nothing untoward anyway.
I will try the OEM discs again, as soon as i can get a day off work, i'm on call at weekends so it's not possible for me to do it then.
I got a new pair of pad pins yesterday to go in as well, just to eliminate them from the equation.
As you mentioned, i'm also starting to think wear and tear in the calipers could well be the culprit, so i think i've got to consider changing them.
More people are born because of alcohol than will ever die from it.
I agree with Gnasher, those calipers are superb. Mine are still performing brilliantly despite having covered an impressive mileage.
It can take a long time to get discs bedded in. I changed mine last October and opted for EBC discs and pads.
They were a bit grabby at low speeds at first and the discs rusted like crazy and would stick hard to the pads when parked overnight if there was any hint of dampness. Oddly, they're now fine, nice and progressive and they don't rust... but it took about 3000 miles of use before they started behaving themselves.
It sounds as though you've eliminated a lot of potential causes, though I do wonder how you can maintain the flatness of the disc to better than 0.001" when rubbing them down with sandpaper.
I'd more suspect the torsional rigidity of the front forks than the calipers. If there's something amiss with the inner surface where the axle clamps them together via the spacer/sleeve and speedo housing then they could rotate slightly in response to the torque applied by the brakes. Maybe that could provoke some sort of resonance effect that then buggers up the discs.
I think if its a wheel associated problem i it would of been there constantly ,regardless of all that you have changed. Have you tried when the judder returns to just part your calipers without cleaning discs or doing anything else & trying again to see if its still there ? Or has anybody on this site got a couple of spare calipers to lend you to try out.
It sounds like your covering the bases its certainly a strange one
TWO sets of forks, exactly same problem, even i can't be that unlucky?
And i am extremely careful when sanding discs, by hand, and because you are getting rid of previous brake markings you can easily see what is going on.
I use aluminium oxide paper, in small circular movements, I tried Garnet paper before but it wasn't quite man enough for the job.
Next time i do it i'll post a photo.
Once they're back on they feel like glass for a few miles, and feel perfectly straight with no judder at all.
I kind of savour the moment every time i take the bike out after they've been done.
More people are born because of alcohol than will ever die from it.
Is it a vibration or a sort of warped disc sort of feel through the lever? I had a similar problem a while back on my FZ1 (warped disc syndrome) and discovered a way round it. The rivets that hold the disc to the carrier get clogged with brake dust over time. The answer is to get a 6mm nut & bolt (10mm head) and push the bolt through the centre of the rivet and nip up the nut so that when turning the bolt the rivet also turns. Squirt brake cleaner around it as you turn it and watch all the crud come out. Repeat with all the rivets. Cured mine a treat.
I've done all that mate, also i'm rotating 3 sets of discs that i have, and i get the same grabbing, on/off juddering effect, it's like braking on cobblestones.
They're definitely not warped at all because it goes away when i clean the discs up for a little while, and if i use the brakes lightly it's not so bad, if they were warped i'd feel it as soon as i touched the brakes even a little bit.
I'm gonna hopefully take Tuesday off next week and give it another go, weekends are no good to me due to work.
If that fails, i think another set of calipers will probably be my next move.
More people are born because of alcohol than will ever die from it.
It sounds like your just randomly trying different things. If I was you I would stop sanding my discs for a start and get the bike to a decent mechanic to ride and try and diagnose.
22-05-12, 01:23 AM (This post was last modified: 22-05-12, 07:26 AM by darrsi.)
"Random's" not a word i would've used to be fair!
I had what i thought was a simple problem and i reacted accordingly, almost by the book.
I started with the obvious and worked my way up.
My bike has been to a few mechanics, and even they've scratched their head?
Which is why i've decided to share my issue countrywide, in the hope that one or more of you nice people can help me out!
This is no joke to me now, i've spent a lot of time and money on this problem and it's kinda peeing me off as you can imagine, if i knew what was wrong i'd have got it sorted ages ago.
I know there's some clever Foccer out there that may be able to help me out!!
More people are born because of alcohol than will ever die from it.
I've given you every possible cause that I believe could cause your problem you saying it's none of the above, that only leaves...................................YOU!
It's something your doing or not doing whether that be not checking all the areas mentioned, incorrectly bedding pads/discs in, incorrectly diagnosing the fault or just making it up.
(22-05-12, 07:45 AM)Gnasher link Wrote: I've given you every possible cause that I believe could cause your problem you saying it's none of the above, that only leaves...................................YOU!
It's something your doing or not doing whether that be not checking all the areas mentioned, incorrectly bedding pads/discs in, incorrectly diagnosing the fault or just making it up.
That sounds a little harsh... the guy is asking for our help, not our ridicule. It's entirely plausible that this is an issue that no one has ever come across before and unfortunately only time and further tests will tell.
Hi
Just a thought, my wife is a very light on the brakes in the car and if I havent used it for a while the brakes glaze up, they judder and squeal and I have to do several heavy braking stops to remove the glaze.
If you happy to down grade the brakes are you a light very braker and its glazed pads and discs.
ATB YFM
Many years back I had a new Mk2 Ford Escort which developed brake judder.It went back to the dealer who fitted softer pads that cured the problem.I had bedded in the brakes as recommended in the first few hundred miles driving.
If you have checked everything from the steering head bearings down and your discs are true & wheel bearings ok, & you are happy with the callipers & pistons-then try some different brake pads.Good luck! But give them a chance to bed down to the discs-it always takes some mileage before they work as they should.
Okay then, the latest news is that the near side caliper appears to have two sticking pots on the same side, and on closer inspection one of them has also formed a bit of rust, which i'm a bit surprised at because they are fully red rubber greased up whenever i clean them, which is about twice a year.
I ride 5 days a week, every week, and i'm wondering if it's just had water settling on those two pots when the bike's on the side-stand at work when it rains? Or maybe salt damage from gritters (just a thought)
Anyway, when i looked at the caliper the pots on one side were pushed out much more than i've ever seen before, but hardly at all on the other.
You can see in the photo that the pads are not central at all, so i'm 'guessing' that the disc was being pushed from one side only and not both sides, and that is what's causing the 'juddering' effect?
Luckily the discs weren't being pushed hard enough to touch the actual caliper body, otherwise that could have got messy.
I won't know without stripping them down but i can only imagine there to be a bit of rust on the pots that i can't see internally as well.
They've always cleaned up okay in the past and moved in and out freely before i've greased them up so i'm a bit disappointed this has happened to be honest.
I put the OEM discs back on, and cleaned up the pots as much as i could, before greasing them up again, and i treated the calipers to some new pad pins as well, but i can't see it lasting too long so i think i'll get another left caliper anyway.
The right caliper was functioning perfectly, and very evenly, but i cleaned that up as well while i was at it.
The pads were still in very good, clean and flat condition, they looked almost new.
I never got a chance to try it out today as i've had a very busy day off, so i'll let you know the outcome tomorrow?
Thanks for all your input and advice, it was very much appreciated!
More people are born because of alcohol than will ever die from it.
Wait a minute, the more i look at that picture the more it just doesn't look right?
Can anyone explain how the surface of the pad on the left can be virtually halfway in between the caliper inner body, surely the disc is fixed and should be in the middle?
Why would the disc be so far over to the right side, and not central like the disc on the other caliper was? :eek
More people are born because of alcohol than will ever die from it.
If the pistons are sticking greasing the outside of the pistons will do nothing.
They are sticking because the seal rebates are corroding which applies pressure to the back of the main seals which in turn grip the piston/s. You need to strip each caliper clean the rebates and replace the seals, all of them!
22-05-12, 08:32 PM (This post was last modified: 22-05-12, 08:34 PM by Gnasher.)
(22-05-12, 08:24 PM)darrsi link Wrote: Wait a minute, the more i look at that picture the more it just doesn't look right?
Can anyone explain how the surface of the pad on the left can be virtually halfway in between the caliper inner body, surely the disc is fixed and should be in the middle?
Why would the disc be so far over to the right side, and not central like the disc on the other caliper was? :eek
That's the problem the pistons on the right have seized, when you apply the brake the pistons on the left are pushing the disc against nothing! This is what is giving you the judder and will if not sorted you will distort the disc if not already.
![[Image: 242673.png]](http://badges.fuelly.com/images/smallsig-uk/242673.png)
![[Image: 174802.png]](http://badges.fuelly.com/images/smallsig-uk/174802.png)
But give them a chance to bed down to the discs-it always takes some mileage before they work as they should.
