Date: 28-03-24  Time: 12:55 pm

Author Topic: FRONT BRAKE CALIPERS / BRAKE JUDDER  (Read 21761 times)

darrsi

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FRONT BRAKE CALIPERS / BRAKE JUDDER
« on: 06 May 2012, 09:06:25 pm »
Does anyone know if there's an alternative to the blue spot front brake calipers, maybe with just 2 pots rather than 4 on each one?
I've had a continuous nightmare with front brake juddering for a few years now, which i deal with by carefully rubbing down discs so they're like new and rotating them about every 6 months which i'm used to doing but is obviously a pain in the arse.
I've got 3 pairs of discs, 2 that were brand new after market discs and 1 set that were 2nd hand originals.
I've been biking for years and never had trouble with any brakes at all that i can remember but this bike is driving me nuts.
It's definitely caused by uneven deposits on the discs because when i clean them up they work perfectly for a while, so they're not warped at all, and i do the recommended bedding in procedure. I've had new discs with new pads, and overhauled the calipers but it still comes back, and there's no leaking anywhere.
In fact up until i realised it was the deposits i've done virtually everything else you can think of, bearings, different pads, discs, even new forks.
The only thing i've not changed is the calipers, so was wondering are there other calipers i could try, OR, is there a trick that i really don't know about that you could enlighten me with?
As you can imagine i've spent a lot of time, effort and money trying to sort this out but i am totally baffled?
I'm open to any suggestions, other than "get another bike" as the rest of the bike is spot on!


It's a 2000 FZS600 S by the way, not that it really matters.


« Last Edit: 06 May 2012, 09:37:06 pm by darrsi »
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Re: FRONT BRAKE CALIPERS / BRAKE JUDDER
« Reply #1 on: 06 May 2012, 10:21:46 pm »
Whats the "uneven deposits" on the discs? (Its difficult to tell from here without seeing it).

Are you running standard compound pads on them discs or upgraded ones?

If it were my bike, I'd want to suss out why the "uneven deposits" keep coming back; changing the calipers may cure the symptom, but not the underlying "disease" if that makes sense.

darrsi

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Re: FRONT BRAKE CALIPERS / BRAKE JUDDER
« Reply #2 on: 06 May 2012, 10:36:21 pm »
Uneven brake pad deposits that get left on the discs that cause a grabbing sensation, or juddering as i call it.
The average person would just say that the discs are warped but i know they're not 'cos when i spend 3hrs each time carefully and evenly rubbing off the outer line wear on the discs they look and feel like new, almost glass like, with absolutely no juddering at all, and they're as straight as anything. I also make sure the rivets on the discs are free from any dirt, and not clogged up either
I've tried several different types of pads, EBC, Ceramic, i'm on Galfers at the moment, yet it still comes back.
That's the weird part, because theoretically if i buy new discs and pads then it should happen on any bike they go on to, so it must be something else causing it.
I clean up the calipers whenever i change the discs and use red rubber grease to lubricate the pistons but to be honest they're so well looked after they don't really need it, but i do them anyway, but i'm wondering if it's something that i can't see.
I've done everything that i can think of so that's why i'm now on here to rack everyone else's brains.
It's pointless taking it to a bike shop as they'll just say change the discs, which will work, for a while, 'cos i've already been down that road and it's not a cheap one!!
I've been a biker for nearly 25 years now, it's always been my only transport so i'm not inexperienced at all, but i'm holding my hands up to this one, i'm well and truly stumped!
« Last Edit: 06 May 2012, 11:28:40 pm by darrsi »
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Re: FRONT BRAKE CALIPERS / BRAKE JUDDER
« Reply #3 on: 06 May 2012, 11:32:31 pm »
That all sounds like a bit of a mystery. The blue spots are incredible calipers giving great braking and I've never really heard of anyone wanting to get shot of them. Sounds like you've been through the list of things that should put the issue right again..


Have you owned the bike from new? has it ever been down the road/offed/cashed?


Have you had anyone else ride the bike to see if they feel the same thing?

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Re: FRONT BRAKE CALIPERS / BRAKE JUDDER
« Reply #4 on: 07 May 2012, 12:12:22 am »
Without seeing the calipers I think you are possibly suffering from pad judder. If you look on the old site there's a posting regarding the "Scot's brake mode".
 
Basically it's your pads moving forward in the caliper due to the design of the retaining spring. The simple brake mod eliminates the movement and ( although it was invented before ) emulates the recent brake spring mods by Yammy.
 
HTH.... Baz  :)
 
PS any more info required then don't hesitate to ask

darrsi

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Re: FRONT BRAKE CALIPERS / BRAKE JUDDER
« Reply #5 on: 07 May 2012, 11:14:33 am »
I've had the bike nearly 4 years, BUT, don't forget i've got a different set of forks on, and the wheel is very straight otherwise i'd get some sort of speed wobble, and it's really rock solid over 100mph. I have braided hoses as well.
I left my bike in a mechanics for a day for investigation last year and they phoned me up later after testing different things and told me to pick it up as they were baffled as well!! They didn't even charge me a penny!


FAZBAZ: I'll have a look at the site now, that sounds like a new one to me!!




UPDATE: I can't find any trace of "Scot's Brake Mod" on the old site, i have emailed FazBaz for more info as it sounds very promising to me.
« Last Edit: 07 May 2012, 12:03:08 pm by darrsi »
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darrsi

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Re: FRONT BRAKE CALIPERS / BRAKE JUDDER
« Reply #6 on: 07 May 2012, 03:03:59 pm »
Ok i finally found the post in the old forum, it's titled "THE BAZHANS BRAKE MOD"


Bit of a shame i can't see the photo's as i would have liked to see how it looks when the retaining spring is put back in place, because from what i've just seen on my bike it will make it a good 4mm longer at the top end so i can only imagine it will arch quite a bit on replacement?


I did however notice that my pads had quite a bit of movement with the pad pin in place so this is definitely a step in the right direction for me at the moment, because i originally thought the slight metallic knocking sound when braking was movement in the semi floating discs!


FAZBAZ: If you by any chance have any photo's of the end result i would very much like to see them. I'm a little bit hesitant to try this straight away as i really need my bike for the rest of the week, and also wouldn't mind locating some new retaining springs first in case i have a disaster!


ALSO: One question i'd like to ask: As the retaining spring is pushed down much firmer than normal, does it effect the side movement at all along the pad pin?

« Last Edit: 07 May 2012, 06:43:19 pm by darrsi »
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Fazbaz

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Re: FRONT BRAKE CALIPERS / BRAKE JUDDER
« Reply #7 on: 13 May 2012, 08:08:55 pm »
Hiya mate, PC problems so I've not been on here for a wee while  :(

I don't have any photos of the brake mod but will post them up. It's been done two ways....

1: As per the old site where the front edge of the retaining spring is hammered flat and the excess length ground off. This lets the back portion of the spring force the pads onto the front face of the caliper rather than rocking into said face every time the brakes are used.

2: I've done this differently on my R6 (same caliper) where I've placed a strip of firm stainless steel banding between the pads and the front of the spring and this sits on the caliper body. Not as tidy but as effective and really quick to do. Also the springs aren't altered in any way.

HTH.... Baz  :)

darrsi

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Re: FRONT BRAKE CALIPERS / BRAKE JUDDER
« Reply #8 on: 13 May 2012, 09:20:07 pm »
Thanks for that Baz.


I did the first mod today and it's certainly stopped the pads from rocking back and forth, they're now held forwards quite firmly.
I noticed the pad pins had started to wear quite recently through all the rattling, i'll probably need to replace them soon so the pads can slide properly.


On the downside, i still had a bit of grabbing/juddering going on still.


I'm hoping that it's deposits on the discs caused by the pads not functioning correctly (i'm totally guessing, i haven't got a clue?), so i think i'm gonna have to clean up another set of discs and start from scratch again and hope with the pads in a firm forward position it will correct itself?
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Re: FRONT BRAKE CALIPERS / BRAKE JUDDER
« Reply #9 on: 15 May 2012, 09:37:08 pm »
Pictures?
Later

darrsi

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Re: FRONT BRAKE CALIPERS / BRAKE JUDDER
« Reply #10 on: 15 May 2012, 10:38:13 pm »
Pictures of what?


You can't see pad deposits by eye, you just feel them grabbing.


I went to work this morning in a virtual monsoon, and it didn't feel too bad at all, so that would aim at a friction problem between pads and discs me thinks.


Now the pads are locked forward after the mod and not flapping about, i reckon if i buff up a set of discs to like new again then break the pads in i'm "hoping" it will all be good again, fingers crossed. (when i say "buff" it takes me about 3hrs to slowly and carefully clean up the face of the discs with aluminium oxide paper in circular movements, until all previous braking marks are gone, it's a pain, but very effective, and they come up like brand new discs)


Just gotta wait for the damn weather to sort itself out first though, i wasn't expecting winter in May......
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Re: FRONT BRAKE CALIPERS / BRAKE JUDDER
« Reply #11 on: 15 May 2012, 10:43:24 pm »
Mate what are you talking about pad deposits!
 
If there is something on the dics you will see it take a picture and post it!
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darrsi

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Re: FRONT BRAKE CALIPERS / BRAKE JUDDER
« Reply #12 on: 16 May 2012, 12:26:12 pm »
This article is based on cars, but i'm presuming brakes are brakes, whether car or bike, the wheels go round, and brakes stop you!!!
http://www.stoptech.com/technical-support/technical-white-papers/-warped-brake-disc-and-other-myths
 
 
« Last Edit: 17 May 2012, 09:12:46 am by darrsi »
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Re: FRONT BRAKE CALIPERS / BRAKE JUDDER
« Reply #13 on: 16 May 2012, 01:45:32 pm »
Interesting article.
Kind of points the finger at break-in technique rather than the calipers as being the cause of your problem doesn't it?

darrsi

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Re: FRONT BRAKE CALIPERS / BRAKE JUDDER
« Reply #14 on: 16 May 2012, 03:11:30 pm »
I've tried every bed-in process you can think of, i've had plenty of time, and attempts at it.
But if you read above, now that i've done this mod and the pads are in a solid position, i'll try a 'clean' set of discs again and i'm hoping it will sort it. The pads were rocking quite a bit, which is apparently wear and tear, and now they're not.
I should have a new set of pad pins tomorrow too, as the old ones had a slight groove forming from the rocking pads.
This has been going on for ages, and the ONLY bike i've ever had issues with brakes, which is a shame 'cos it's a fantastic bike otherwise?
 
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Re: FRONT BRAKE CALIPERS / BRAKE JUDDER
« Reply #15 on: 17 May 2012, 02:51:21 pm »
A bit random but have you looked at your fork bushes at all? if they are worn the bushes will move from side to side giving the appearance of judder just a thought. :) 

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Re: FRONT BRAKE CALIPERS / BRAKE JUDDER
« Reply #16 on: 17 May 2012, 03:32:20 pm »
I've tried every bed-in process you can think of, i've had plenty of time, and attempts at it.
But if you read above, now that i've done this mod and the pads are in a solid position, i'll try a 'clean' set of discs again and i'm hoping it will sort it. The pads were rocking quite a bit, which is apparently wear and tear, and now they're not.
I should have a new set of pad pins tomorrow too, as the old ones had a slight groove forming from the rocking pads.
This has been going on for ages, and the ONLY bike i've ever had issues with brakes, which is a shame 'cos it's a fantastic bike otherwise?

 By the share fact whatever it is has a deposited it's self on the disc/s can only get from either the disc tearing up the pad or the pad tearing up the disc or something being thrown onto the disc.  If you are using cheap pads/discs or fake quality parts it's very likely you can get deposits, again normally you notice a serious drop in performance long before and deposits.     The caliper/s could be causing the pads to bind on the disc that said providing you are using quality disc/pads you will not get deposits in normal use you will get a loss of drive and brake fade long before deposits.  Blue spot calipers and the later gold spot radial calipers are second to none many track day fans and club racers dump the standard calipers on their CBR's, XZR's, GSXR in favour of blue/gold spots.   Post some picture of the deposits and the pads and we can go from there.
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darrsi

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Re: FRONT BRAKE CALIPERS / BRAKE JUDDER
« Reply #17 on: 17 May 2012, 05:01:09 pm »
New wheel bearings,
Head bearings,
Around 4 different types of pads, using Galfer at the moment
Including the original ones i naively binned, 4 sets of discs (2 x original Yamaha, 2 x aftermarket)
Changed forks (painted up old ones and sold them, didn't lose anything)
Front wheel is faultless, and perfectly straight, had a mechanic check it out, no speed wobble at all
New seals on calipers, and i clean them up every 6 months, although they don't really need it, and use red rubber grease on the pots
Braided hoses
New brake fluid, and bled properly
Brake master cylinder refurbished (repair kit)
When i clean up a pair of discs, NO JUDDER for a while, then it slowly creeps back.
THIS IS THE REASON I AM ON THIS FORUM, I AM BAFFLED!!!
Sooooooo, the idea of the brake caliper retaining pad mod was a breath of fresh air to me, 'cos i would never have guessed that at all.
And as i've had new pads and discs before it still aims towards the calipers, I THINK, but i don't know???
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Re: FRONT BRAKE CALIPERS / BRAKE JUDDER
« Reply #18 on: 17 May 2012, 05:26:11 pm »
Pictures  ;)
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darrsi

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Re: FRONT BRAKE CALIPERS / BRAKE JUDDER
« Reply #19 on: 17 May 2012, 08:28:10 pm »
Gnasher, i am hearing you mate, but there's really nothing to look at to be honest?


The discs are totally normal to look at, with even disc rotational markings.


If you read the website i posted before it does say that if there were 'deposits' then you wouldn't be able to see them anyway, which i can't!


Believe me i've spent so much time handling discs over the years i'd spot an abnormality a mile off it was visual.


The fact that i've had different new sets of pads and discs and the same problem has reoccurred theoretically rules them out as a source of the problem, they're just a reaction to the issue.


I'm trying to eliminate things in my mind but as you can see from my earlier post i've tried the majority of things, apart from a new caliper or wheel.


I really don't believe it's the wheel, so that leaves the caliper, which i never really suspected before because it all seems to be functioning ok.


It's not even the type of problem to give to a bike shop because they'll just say get new discs and pads, and that habit is getting way too expensive!


 ***** THE LAST PHOTO SHOWS THE BRAKE PAD RETAINING PLATE MODIFICATION *****


2mm taken off the bottom edges (the very lowest lip part), and the top part completely flattened out with a hammer until it is a straight, flat piece of plate metal. (the arrow on the pad should be at the bottom pointing upwards, the same way as wheel rotation)


It's a much tighter fit when put back on, and holds the pads in a forward position only, so they can't rock back and forth.
 
NOTE: There is no bent over lip on the top left part of the plate in the photo, it is completely flat, the photo and grubbiness(crappy weather, sorry), makes it a little bit deceiving!
« Last Edit: 18 May 2012, 09:55:00 am by darrsi »
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Gnasher

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Re: FRONT BRAKE CALIPERS / BRAKE JUDDER
« Reply #20 on: 18 May 2012, 01:34:00 pm »
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!!!   
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darrsi

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Re: FRONT BRAKE CALIPERS / BRAKE JUDDER
« Reply #21 on: 18 May 2012, 02:31:27 pm »
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.
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Re: FRONT BRAKE CALIPERS / BRAKE JUDDER
« Reply #22 on: 19 May 2012, 09:35:47 am »

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.

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Re: FRONT BRAKE CALIPERS / BRAKE JUDDER
« Reply #23 on: 19 May 2012, 10:55:06 am »
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



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Re: FRONT BRAKE CALIPERS / BRAKE JUDDER
« Reply #24 on: 19 May 2012, 11:04:52 am »
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.
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