Discs Warping - A cause if not A Cure? - Ducati.ms

Johnny · Jan 18th, 2012, 9:57 am

Something like year 8 of my battle with braking vibrations. New Discs N0.4 on the front and new seals and brake strip down. I have replaced and serviced the entire front end (bearings/forks seals etc)

I know many ST's have gone like this and the entire front end is fairly high quality so could it be the illogical front spindle tightening routine that is causing this on so many bikes?

stryder · Jan 18th, 2012, 10:32 am

Quote:

Originally Posted by Johnny

Something like year 8 of my battle with braking vibrations. New Discs N0.4 on the front and new seals and brake strip down. I have replaced and serviced the entire front end (bearings/forks seals etc)

I know many ST's have gone like this and the entire front end is fairly high quality so could it be the illogical front spindle tightening routine that is causing this on so many bikes?

Are you saying you have replaced you discs 4 times? If not/ or if yes, what type of disc? The same Brembos with, what, 10 bottons? If so, and if like I feel, the issue is primarily with the rotor bottons, ie some are tighter than others especially over time and dust accumulation, (and secondly with brake pad material transfer) and you haven't modified them or replaced them with full floaters (and tried different pads) that might be another avenue for you to explore.

Re your spindle theory: perhaps, but then one would assume all riders who have this issue, which appears on many Ducati models as well as other brands, are misaligning their forks.

Johnny · Jan 18th, 2012, 11:16 am

Quote:

Originally Posted by stryder

Are you saying you have replaced you discs 4 times? If not/ or if yes, what type of disc? The same Brembos with, what, 10 bottons? If so, and if like I feel, the issue is primarily with the rotor bottons, ie some are tighter than others especially over time and dust accumulation, (and secondly with brake pad material transfer) and you haven't modified them or replaced them with full floaters (and tried different pads) that might be another avenue for you to explore.

Re your spindle theory: perhaps, but then one would assume all riders who have this issue, which appears on many Ducati models as well as other brands, are misaligning their forks.

Well I replaced them 3 times so this is set 4. After the OEM's I had EBC's. which were replaced once for pitting (rust!) and again as the replacements were checked and found to be OK but " but they had the early outer rotors on them – so they were replaced with totally new discs with the latest production hardened rotors"

All discs have been semi floaters. I “feel” that the buttons issue may be overplayed (please ping if you tried it and it worked) As for pad material I tried all types and bed in methods, plus cleaning and rebedding. My latest attention is that one of the replaced seals was partially broken. I am hoping this and the new discs shall cure it – but I have been here before

**Gearbox** · Jan 18th, 2012, 11:47 am

Loosening the buttons worked for me , basically wore out the discs (45,000 Mls).

One issue that can be overlooked is the possibility of pad material transfer caused by sitting on the brakes for too long once stationary.
I.E. running hard and fast and then arriving at a stopping point where you need to stay stationary for any significant amount of time. It is then advisable , if possible , to release the front brake and 'hold' the bike on the rear.

Not saying it is the issue with you (actually you dont seem to have had it as bad as some as 2 sets replaced were not related to juddering) , or for that matter all , but it is an issue to be considered when having this problem and looking for a cause/solution.

It is certainly very rare , if ever , warped discs as some dealers try to blame.

Johnny · Jan 18th, 2012, 1:48 pm

Quote:

Originally Posted by Gearbox

Loosening the buttons worked for me , basically wore out the discs (45,000 Mls).

One issue that can be overlooked is the possibility of pad material transfer caused by sitting on the brakes for too long once stationary.
I.E. running hard and fast and then arriving at a stopping point where you need to stay stationary for any significant amount of time. It is then advisable , if possible , to release the front brake and 'hold' the bike on the rear.

Not saying it is the issue with you (actually you dont seem to have had it as bad as some as 2 sets replaced were not related to juddering) , or for that matter all , but it is an issue to be considered when having this problem and looking for a cause/solution.

It is certainly very rare , if ever , warped discs as some dealers try to blame.

Just to clarify, all discs except these brand new ones vibrated. I must have cleaned and re padded half a dozen times and it did not cure it. My money is on that seal though, we shall soon see

Puffin64 · Jan 19th, 2012, 8:01 am

I had brake judder with the stock disks and calipers which was nearly an MOT failure, but only an advisory this time round.
I decided to change my rotors to wave disks nearly new from ebay and a set of P4 calipers, I've not had any problems since and can brake with confidence one fingered.

**Gearbox** · Jan 19th, 2012, 8:24 am

John , What seal are you referring to and why do you feel it would cause brake judder ?

Johnny · Jan 19th, 2012, 11:54 am

Quote:

Originally Posted by Gearbox

John , What seal are you referring to and why do you feel it would cause brake judder ?

Brake piston seal, it was broken/and or some crud was under there. This would cause the piston not to move as freely causing uneven pressure on the disc and judder. One pad was more warn than 'tothers

All IMHO

tonered · Jan 19th, 2012, 8:11 pm

I posted something similar in the pads and tires thread a couple days ago. One of the left side pistons was solidly hung up. It had a nice ridge of brake dust built up on it. That said, all the others had some on them. I was only able to ride two days before snow hell came to town. I'm hoping from some seat time this weekend. With everything pristine though, the pistons don't back off very much at all. The lever is firm at any touch and the only visible movement is the pad clamping down.

It does seem that a caliper rebuild would be an easy effort. Bleeding was no problem at all with a bleed nipple on the master.

Have a good one.

Corse1 · Jan 20th, 2012, 1:10 am

Loosening the buttond by prying the inner petals open worked for me but I must say that LH rotor is loose now but my RH one which has always been the problem has not loosened as much. Doesn't wiggle with free play like the left now does. It must be enough as after 5 years of cleaning and checking rotors I am finally vibration/pulse free.

I know my rotors were straight and true after checking with DTI on a granite toolmakers surface.