(Breva 1100) Front Wheel, brake rotors

[lionsrest]

(Breva 1100)The problem I'm trying to remedy is brake pulsing, especially at lower speeds approching full stop.
It has finally become annoying enough to take action.

I checked out all the 'floating rivets' but am now convinced they're not the problem.
Using a makeshift 'dial guage', I can easily detect high and low spots on the disc surface.
Correct me if I'm wrong, but I believe what's needed in that case is a resurfacing.

If so, now I'm faced with removing the front wheel, and getting the discs off the wheel to send them off and get them resurfaced/turned/whatever the term is. This is seeming to be a surprisingly difficult task.

Not finding any definitive instructions, I basically muddled through getting the front axle out, but I can't get the wheel past the brake calipers and off the bike. The allen bolts holding them onto the forks are enormously tight. (Factory Loctite?)
Thinking I could just remove the discs now that the axle is removed, I run into the same thing.
Reading about it in the old archive, and assuming it applies to my Breva 1100, I can see this is quite a process. :blink:

So, my questions are:
Am I correct in that the discs need to be resurfaced, or is there some other way to eliminate the pulsing I've overlooked?

Is there a trick to removing the front wheel without removing the brake calipers?

If I have to remove the brake calipers, do I need to heat the bolts up a lot to break them free (Loctite used)?

Do I also need to use the heat technique to get the discs off the wheel on the Breva 1100?

What are the chances of success without an impact wrench?

Am I better off just putting this in the hands of a dealer?

 

[john zibell]

OK Here goes,

You have to remove the calipers. Get a 7mm hex socket on 3/8 drive to remove them. Only use heat if absolutely necessary, and only apply heat to the Allen bolts.

Forget re-surfacing the rotors, they are darn thin to begin with. Check with Todd to see what is available for new rotors and pads.

To remove the rotor bolts, again use a good socket and heat the devil out of the Allen screws. Once they have been thoroughly heated they remove easily. On re-install use loctite 242 (blue). It prevents corrosion and will allow for easier removal in the future. The article you reference applies to the shitty button head screws that were used in the past. The ones in the newer bikes seem to be of higher quality.

Since it is a B11, I presume you have had a tire change? Where ever you took it, don't take it back. It seems they really over tightened the bolts for the brake calipers.

 

[Retro]

A similar well known problem with the wavy discs on the 1200 sport, happenning at all speeds, believed to be warpped discs (some managed to win the warrentry claim game, but MG have put a stop to that), but later belief, it may be the pad material contaminating the discs.

One suggested cure is to go out and really abuse those front brakes, it seems to clean up the disc. It work on mine, just a faint pulsing at very low speed on light braking remains. Some owners have commented that a change of pads eg. EBC, eradicates the problem.

 

[GTM®]

John covered most of it above. The hex-head bolts on the newer bikes are much easier to remove compared to the buttery-soft allen heads on models past, which is what the above link was referring to.

The "snowflake" Brembo rotors that come on the newer Guzzis are actually decent disks... though they have been somewhat problematic to pulsing as documented here. The friction disks cannot be turned or resurfaced, because the carrier-to-rotor "buttons" are not user serviceable. They are only meant to be replaced unfortunately. Usually a pulsing disk can be remedied the cleaning the buttons with brake cleaner and compressed air, and often a hammer and socket hit on the buttons (covered in a post by Graham, do a search). If that doesn't revive them, they have to be replaced. As a Brembo dealer, I'd be happy to get you a price.

Brembo offers a sintered "HH" pad like EBC that isn't as hard on the disks as the EBC's. They are $56/pair. If you use the EBC's, be sure to put a micrometer on the disk after the set wears out, and look for stress fractures (cracks) around the holes drilled in the friction disk.

Hope that helps. Feel free to contact me direct for any other questions regarding replacement/pricing. Happy to help.

 

[3ackok]

If I have to remove the brake calipers, do I need to heat the bolts up a lot to break them free (Loctite used)?

I removed the calipers for tire and fork oil changes. No problems with bolts, other than a fact that my Hex sets didn't have a 7mm wrench.

 

[lionsrest]

Man, what a helpful bunch! Thanks!

Talking with TrueDisk in Carleton MI, ( http://www.site.truedisk.net/ ) they've been indicating they can resurface the discs. I asked if I needed to remove the actual braking surface part from the floating 'frame' and they said no. I even sent a link to a picture. Not sure what to make of that now.

I've read several posts regarding the buttons, and went at mine with a pressure washer, and then air compressor. I made sure to blast them from every angle, and dry it all thoroughly. I checked to make sure every one of the buttons on both discs could be turned by hand, but weren't rattling loose. None of that made a bit of difference to the problem of pulsing.

Checking the disk 'flatness' by carefully holding a plastic stick of some kind barely touching the disk surface and anchored against the fork and then rotating the front wheel (a crude dial guage of sorts), I could detect high and low spots. This is what has sent me down the path pursuing resurfacing. I'm pretty sure this is the culprit, not the buttons.

So, if they, as GT-Rx says, have to be replaced, I could use a price. I've been rather horrified by what I've seen so far... well over $600. I've seen EBC rotors at JC Whitney's for about $200 less, not sure what to think about those.

 

[GTM®]

Brembo "Snowflake" replacements are <$150 per disk.

 

[Roblatt]

I have an 06 B11 which suffered the same problem. I was told it was a warped left disk. I was also told to go out and abuse the front brakes before spending money. No more pulsing at any speed. I just abuse the brakes regularly now.

The Italian engine tune up for Alfas, seems to work on Brembos too.


Robert

 

[Penis Rotor]

Todd? How much are 'Conventional' discs rather than the 'Braking' petal rotors used on the G8? I think I'll swap to them when the rotors on mine wear out as I'm not a tremendous fan of petal rotors. (Thet the flaming begin!!! :lol: )

Pete

 

[GrahamNZ]

Pete

Fitting a Braking brand wave rotor is the only cure for a distorted ZTL rotor on a Buell. Not the same as a wave rotor admittedly, but follows similar principles of providing a heat expansion path that doesn't distort a rotor.

BTW the brakes on my Breva have given no trouble since loosening the rivets (mounting bobbins) about 40,000km ago. Smooth as silk and with plenty of feel and power. I do enjoy hard braking and around here there's plenty of opportunity for it.

A tip - after hard braking it's not a good idea to stop and then hold the brakes on as that can lead to uneven cooling of the rotors. Ditto for parking cars when it's better to just leave the car in gear unless there are separate parking drum brakes at the rear.

 

[Roblatt]

A tip - after hard braking it's not a good idea to stop and then hold the brakes on as that can lead to uneven cooling of the rotors. Ditto for parking cars when it's better to just leave the car in gear unless there are separate parking drum brakes at the rear.[/quote]


I didn't know that. Thanks Graham.

Robert

 

[Zapa]

Just in case there's some pad residue in the discs, and just to be sure before you pay for new discs, use brake cleaner and a 3M Scotchbrite or similar to give them a good clean.
When you think you've cleaned them fully, clean them again, then mop the surface with a cotton cloth.

Give it a try. Who knows, it might save you a few bucks.

 

[lionsrest]

Brembo "Snowflake" replacements are <$150 per disk.

If that is the whole assembly, Snowflake 'frame' + buttons + braking surface all put together, not just the braking surface alone, I'm interested!

A tip - after hard braking it's not a good idea to stop and then hold the brakes on as that can lead to uneven cooling of the rotors. Ditto for parking cars when it's better to just leave the car in gear unless there are separate parking drum brakes at the rear.

... I'd always suspected that! Kind of hard to avoid when you have to stop on a hill, but otherwise a great tip.

Just in case there's some pad residue in the discs, and just to be sure before you pay for new discs, use brake cleaner and a 3M Scotchbrite or similar to give them a good clean.
When you think you've cleaned them fully, clean them again, then mop the surface with a cotton cloth

Will try that, but after detecting high/low spots, I think it's probably more than residue causing this pulsing.

BTW the brakes on my Breva have given no trouble since loosening the rivets (mounting bobbins) about 40,000km ago. Smooth as silk and with plenty of feel and power. I do enjoy hard braking and around here there's plenty of opportunity for it

I don't have much opportunity for hard braking. I worry about loosening the mounting bobbins so much that while it may mask the pulsing problem, the strength of the brakes are compromised. I've heard others say they got them so loose they jingled/rattled... this just seems potentially dangerous to me, yet no one has had a failure with this technique :? . Plus with the dry clutch rattle, people will hear me for miles

 

[GTM®]

Brembo "Snowflake" replacements are <$150 per disk.

If that is the whole assembly, Snowflake 'frame' + buttons + braking surface all put together, not just the braking surface alone, I'm interested!

Yes it is, as shown below.

 

[Spaceclam]

as long as you dont fatigue the buttons by loosening them, you do not compromise strength. the force on the disks are axial, which is why floating rotors work in the first place. But how do you know you havent fatigued them?

The CSUN formula team makes their own buttons, and when the brakes start to warp during the race, they just replace the buttons with smaller ones because they are held on only with a circlip, since there is no load pulling the buttons out. They start out with tight buttons because there will be less drag, and they change them in the 30 secs it takes to change a tire. only 4 buttons/rotor.

 

[GrahamNZ]

I don't have much opportunity for hard braking. I worry about loosening the mounting bobbins so much that while it may mask the pulsing problem, the strength of the brakes are compromised. I've heard others say they got them so loose they jingled/rattled... this just seems potentially dangerous to me, yet no one has had a failure with this technique . Plus with the dry clutch rattle, people will hear me for miles

Hmmm. Hard braking can and should be practised often to keep the rider and brakes in readiness for an emergency stop. While I have the luxury of many roads with sharp bends to use, a straight road is just fine for brake and rider exercise. Make sure no one is close behind of cource!

Others have pointed out that there is little lateral force on the bobbins. Shearing one would be extremely unlikely.

Race bikes often have the floating rotors so free that they rattle, to ensure that they are free to self-align to the calipers. Rattling bits are just part of the Guzzi character, so why worry about another insignificant one? BTW the bobbins don't have to be rattlingly loose, just loose enough that you can rotate them between your thumb and forfinger.

 

[Zapa]

In fact my bobbins are fully floating ones. I substituted the originals for replacements I bought from Xparts.

Do they rattle? Yes. Do I care? Not much I prefer not having to "soften" them up from time to time.

 

[lionsrest]

Well the good news is that I didn't have to resort to heat/flames to get the wheel and a disc off.
Got some proper tools, an impact driver and hex (allen) bits instead of the allen wrenches. Not a problem anymore.

Going to try and loosen the bobbins somewhat, and carefully clean the braking surfaces.
If it's still pulsing badly, I'll probably get a new disc or two.

I don't mind some extra rattling, I agree it's part of the Guzzi character. Certainly doesn't worry me. I knew loosening them up isn't dangerous, considering I've not read one complaint or warning of it being unsafe, but it just seems counterintuitive having even slightly loose parts somehow.

I mainly commute to work on the Breva, and I ride and brake gently to get max fuel economy and minimum wear/tear.
I agree I should find some time and proper location to practice hard braking and probably help reduce the pulsing.

Thanks to all, I definitely value all the feedback!

 

[rturo]

Hi

I'm suffering some pulsing under normal breaking especially when reducing lever pressure to lose speed rather than actually stop. I intend trying the recommended real heavy braking to see if this helps - I plan to do it just before i swap out the pads so that if i glaze them its the old set of pads not the new.

Regarding the cleaning of the bobbins I'm not sure how much movement there should be, but there sure isnt any at the moment. Looked through the toolbox to see what might help loosen them and found that a metalworkers tapered centrepunch slides right in until tight and allows me to wriggle the bobbins to get the brake cleaner where its needed and allow the bobbins to move freely again.

Art
Breva 1100

 

[Zapa]

I'm suffering some pulsing under normal breaking especially when reducing lever pressure to lose speed rather than actually stop. I intend trying the recommended real heavy braking to see if this helps

You can clean them up. It's the same thing, but done with tools instead of pads
AFAIK it's really hard to glaze used pads. I wouldn't worry about that.

Looked through the toolbox to see what might help loosen them and found that a metalworkers tapered centrepunch slides right in until tight and allows me to wriggle the bobbins to get the brake cleaner where its needed and allow the bobbins to move freely again.

The Guzzi provided screwdriver will do the same job perfectly well