Author Topic: FRONT BRAKE CALIPERS / BRAKE JUDDER (Read 22032 times)

taksi · « **Reply #25 on:** 19 May 2012, 11:45:33 am »

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.

Taksi

CRH · « **Reply #26 on:** 19 May 2012, 11:57:05 am »

i dont think you can do that with the 600 mate? they got a solid ring!!! well mine has thats a foxeye 2002 !

darrsi · « **Reply #27 on:** 20 May 2012, 06:06:15 pm »

@taksi

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.

janner_10 · « **Reply #28 on:** 20 May 2012, 08:20:02 pm »

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.

darrsi · « **Reply #29 on:** 22 May 2012, 01:23:30 am »

"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!!

Gnasher · « **Reply #30 on:** 22 May 2012, 07:45:35 am »

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.

darrsi · « **Reply #31 on:** 22 May 2012, 09:14:07 am »

Yeah that must be it Gnasher, i'm just making it all up so i can have a nice chat ???

I'm off work today, so gonna give the calipers another clean up, and put the OEM discs back on.

Dead Eye · « **Reply #32 on:** 22 May 2012, 11:29:43 am »

Quote from: Gnasher on 22 May 2012, 07:45:35 am

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.

YamFazMan · « **Reply #33 on:** 22 May 2012, 12:36:41 pm »

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

Dave48 · « **Reply #34 on:** 22 May 2012, 06:13:08 pm »

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.

darrsi · « **Reply #35 on:** 22 May 2012, 07:58:35 pm »

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!

darrsi · « **Reply #36 on:** 22 May 2012, 08:24:27 pm »

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?

Gnasher · « **Reply #37 on:** 22 May 2012, 08:27:50 pm »

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!

Gnasher · « **Reply #38 on:** 22 May 2012, 08:32:10 pm »

Quote from: darrsi on 22 May 2012, 08:24:27 pm

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?

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.

That's why I asked you to post pictures matey

red98 · « **Reply #39 on:** 22 May 2012, 08:36:03 pm »

when cleaning the calipers are you popping the pistons outof the caliper or just cleaning what you can see ?

darrsi · « **Reply #40 on:** 22 May 2012, 08:40:58 pm »

That's exactly what i was thought earlier.

But, shouldn't the disc be central in the caliper? How can it drift to the right side?

If the pots on the right have seized, fair enough they'll just stay put, but why should the ones on the left go that far over, because surely the disc can't physically move over because it's bolted down in a fixed (central) position??

darrsi · « **Reply #41 on:** 22 May 2012, 08:44:34 pm »

@red98

I push them out one at a time as far as i feel safe, without popping the seals, then clean them up and re-grease them.

Gnasher · « **Reply #42 on:** 22 May 2012, 08:46:35 pm »

Quote from: darrsi on 22 May 2012, 08:40:58 pm

That's exactly what i was thought earlier.

But, shouldn't the disc be central in the caliper? How can it drift to the right side?

If the pots on the right have seized, fair enough they'll just stay put, but why should the ones on the left go that far over, because surely the disc can't physically move over because it's bolted down in a fixed (central) position??

The discs is just that discs of thin metal the pistons are hydraulic and will easily bend a disc twice the thickness. The discs fitted to the Fazer are what is known as semi floating i.e. the disc is allowed to move side to side slightly.

Gnasher · « **Reply #43 on:** 22 May 2012, 08:55:22 pm »

Once the pistons seize there is no point in pushing them back all you are doing nothing!

If the piston require any more than finger pressure to push them back they are starting to seize time to service the caliper. As I said before these are amongst the best caliper available they are GP race spec of 20yrs ago, all they did to make them road fitment was fit a dust seal.

They need looking after regularly.

darrsi · « **Reply #44 on:** 22 May 2012, 09:04:13 pm »

Yeah, the ones i took off were more floating than the OEM's, you could move them by hand.

I'll see how it goes tomorrow, but the fact that i've got rust on pots which will likely need renewing, plus the cost of seals, etc, i think i'll look for a fully working 2nd hand caliper in good nick.

It'll give me a spare to play with in my own time as well.

The other side was working really nicely.

As much as i like working on the bike i simply don't get the time to do it because i'm on call for work at weekends, so i need the easier and quicker fix.

Thanks for the advice again.

Gnasher · « **Reply #45 on:** 22 May 2012, 09:24:00 pm »

Rust spots on the pistons are coated any rust will just be just on the surface and easily removed providing someone hasn't tried pulling them out with pliers or they are pitted due to over cleaning with wire brushes.

Just service the caliper word of warning you've got to know what you're doing or it could all end in

darrsi · « **Reply #46 on:** 22 May 2012, 09:54:01 pm »

In all fairness, it looked like the rust was more to the outer edge of one of the pots that touches the pads.

I wouldn't be surprised if it's due to all the salt that gets chucked about during our 6 month winters!!

I've actually just ordered a fully working pair of 2nd hand calipers (it was only a few quid more to buy both rather than just one), so at least i can service them in my own time and i can swap them over quickly when needs arise in the future.

I kinda like that idea.........

darrsi · « **Reply #47 on:** 23 May 2012, 09:22:50 am »

UPDATE:
I can only describe my ride into work this morning as 'perfect'.
No hint of judder at all, lovely smooth braking.
A Foccers dream......
I'm a happy man

Dave48 · « **Reply #48 on:** 23 May 2012, 09:56:22 am »

As Gnasher says a picture tells all. If the pistons dont move freely in AND out its a total calliper strip,clean & replace all seals. Should be the end of all your woes-these are the best brakes Ive had on any bike

Dead Eye · « **Reply #49 on:** 23 May 2012, 10:23:57 am »

Mystery solved! Glad you've got it working properly again ^^