Hi all, I'm experiencing a bit of a problem with the above. I have fitted M4s to my MTS12 with sintered pads. The brakes work great, but I have noticed the wheel no longer spins as freely as it used to with the old calipers. I am fairly sure that when I fitted them last time they did not drag. I cleaned the calipers before refitting, and can easily push all of the pistons back. I fitted new HH pads, and I've bled the whole system through with RBF600 fluid, so fairly confident there is no air in the system. I also did the usual fork alignment thing before clamping up the spindle. So my question is, what is causing this, and if its not normal (which I doubt), what is required to fix it ? I'm pretty sure the 1098/1198 etc that these calipers are usually fitted to don't suffer this. We are off on a 10 day trip in 2 weeks, so this is getting a bit of a concern The brakes don't squeal, work great, but the discs are consequently always warm when I stop, and no doubt the pads / discs are going to wear considerably. Any help or suggestions much appreciated. Cheers, John.
I just had a thought - could this be the pads are somhow binding on the calipers, or I've fitted the pad spring wrong ? It was a bit of a game trying to get the spring in, so wondering if its operator error... Daft question, but what if I ran without the spring, can the pads fall out or will they just chatter ? Any thoughts, or pictures as to how the spring should be fitted would be great please.
did you leave enough of an air gap in fluid reservoir? if your system was bled with the pistons extended, then you pushed the pistons back to take new pads you will have pushed fluid back up into the reservoir, if theres no room for the fluid the system will be over pressurised and the pads will drag you could just take it for a quick spin on a fast rd and see if some heat in the brakes beds them in
Thanks for the thoughts. i originally bled it with pistons pushed back, and then as the fluid came through it obviously pushed them out. since then I've put the rest of the bottle if fluid through in two or three goes. i have set the fluid level at the max. It might be worth me dropping the level a bit though, gotta be worth a try. i took it for a blast last week, and also yesterday. The brakes are definitely bedded in, but the pads just dont seem to retract back from the disc. i am now thinking I need to remove and strip the calipers to make sure all the passages are clear. beyond that I have two choices: ride it as it is or refit the standard calipers...
Another though with regard to the fluid level - is it possible to over tighten the master cylinder cap and so stop it venting / stop the fluid retracting ? grasping at straws here.
Thanks matt. If I spin the wheel it stops after about 1.5 turns. It had it's first mot a couple of weeks back and they were border line going to fail it on this. I also rang Snells today and they told me the 1098 / 1198 which use the same calliper I have definitely don't do this. My fall back is to check them regularly and take a second set of pads on our trip, but was hoping someone knew what the likely cause was. Glad I'm not the only one experiencing this though
Have you put the calipers on the right way, there's an arrow to indicate direction of wheel rotation? Do the pads move freely in the caliper? Were the calipers new? When the pistons moved freely was this with the hoses connected and everything bleed. If there is not enough free play between the master and lever the pads won't return properly. The spring steel piece should have the long wide end at the same end as the point of the arrow, the two up ward bent pieces pointing out from the disc and against the raised bit in the centre of the caliper, the 2 tongues on the other end fit into the forks in the pad (hope that makes sense).
Are your calipers centrally aligned with your discs? Did you use WD40 to clean the calipers? This can cause the seals to swell up and bind the pistons. Is your master cyl fully releasing the fluid back? Crack off the banjo at the master cyl to see if it releases any pressure on the calipers. Sorry for the way this looks, paragraphs not working.
Thanks for the comments. The calipers will only go on one way, or the banjo holes are at the bottom :biggrin: I pushed the pistons back in, slackened everything off, and then ensured the discs / pads were central when I tightened it all back up again (I applied the brakes prior to bolting them up to ensure they weren't at an angle to the discs too). I used brake cleaner and a tooth brush, along with an air line and a bit of an old T shirt. Same I've done on all my brakes, so would be surprised if its that. I bled the master cylinder too, so no air up there. No the pads don't really move that freely in the caliper. If I push them back off the disc then I can move them about, but I think the spring is holding them too tight, so experimenting now because i think the spring is fitted wrong. Will let you know how I get on.
Wehey - its fixed ! well, not completely, but miles better. I'm not entirely sure why, but I removed the calipers, pulled the pads & springs, pushed each of the pistons to check none were stiffer than the others. I thought the spring might have been wrong, but it seems the wide bits of the springs can't go in the middle cut-out of the pads, because it is way too loose then. It actually presses below one of the ears ( look at this link to see what I mean about cutout and ears: Ferodo Front Brake Pads, XRAC Racing Pads, For Brembo 1098 front brake calipers | ca-cycleworks.com ) and uses the cast web as a sort of pivot point. anyway, all back together, quick ride around the block with a few heavy stops, and now the wheel will rotate 3 or 4 times if I spin it when on the stand, rather than one and a half before Thanks all for your comments. Much appreciated.
Trying to upload some pics from my phone, thought these were meant to be easy ! Lol if I put the spring ends between the ears on the pad, then the spring wasn't really doing anything. It just rattled around itself (this with caliper in my hand, not fitted to bike). i may have it wrong, but it sort of makes sense as it holds the pads up to one end, tightly in my case. will have another go at posting the pics later.
is it possible to misfit these shims then John? it would serve as a warning to others if it were possible. Have to say it looks pretty foolproof as if you 'splayed' the trailing ears of the shim it looks as though they would be scraping both sides of the disc?
Phew, I did put them in right. My memory must be going and I'm nowhere near the average Ducati rider age.
Sorry to be dragging up and old thread but, I've got exactly the same issue and can't seem to fix it! My braking setup is: - Brembo 19x20 RCS master cylinder - Stainless Steel lines - Brembo M4 calipers - OEM discs - Motul RBF 660 DOT4 brake fluid - EBC GPFAX brakes pads OR SBS Dual-Carbon brake pads After a 20min track session with plenty of heavy braking (6th down to 2nd) I pull into the pits and the bike goes up onto the paddock stands but the front wheel only manages to spin about 1/4 turn before stopping. For some reason the pads are dragging way too much on the discs. I assumed it might be the EBC GPFAX pads which were the problem as they've got such a high braking coefficient so for the next track day I sanded the discs down and went with the SBS Dual-Carbon brake pads as I used to always run these and know what they're like. Next track day, 20 min session....back into the pits and the same problem. Now this is where I started to get into paranoia mode! Could it be the 19x20 RCS not letting the fluid back up? So I swapped the 19x20 RCS for the OEM master cylinder (fluid level in the reservoir always set at half) and after the next session, same problem. I guess the 19x20 RCS isn't to blame here. Next thing I did was pull off the Brembo M4 calipers and on with the OEM calipers, I was gutted at having to do this but it had to be done. Unfortunately I only had my road pads (BRAKING) for the OEM calipers so the braking was crap on the track but back into the pits after 20min, bike up on the paddock stands and no caliper binding! The front wheen now spins freely, about 2 turns before stopping. Through a process of elimination, the source of the problem are the Brembo M4 calipers and the problem isn't related to the type of pads (EBC GPAX or SBS DC) used with them. Now comes the big question, what could be wrong with the Brembo M4 calipers? They're brand new and I've never had Brembo calipers before so is this normal? I'm guessing it isn't because the pads were dragging very heavily. Could it be the OEM discs? Sorry for so many questions but after two long days on the track dealing with brake issues, this is really driving me crazy!
Fluid in the reservoir is set at half way between LOW and HIGH. Thing is replacing the M4 with OEM makes the problem go away!
