Brakes Dragging, Not The Usual Suspects...help!

Just bought an 02 VTEC with 12000 miles.  The front AND rear brakes are dragging on the pads.  They drag hard enough to stop the bike when the fluid gets hot.  I have tried bleeding the system, checked front and rear master cylinders, cleaned pistons, "bounced" the front end, still dragging.  WTF?!?!  I did notice that the tab on the front master cylinder which holds the banjo bolt in place has been cut off at some point, not broken, but actually cut with a dremel or some other tool and filed smooth.  However, the MC itself looked good, no blockages or boogered seals.  What do I do next?!?  Replace the master cylinder?  Leave the bike downtown with the keys in it?

Hi Hycide, welcome to VFRD   :musik20: {the first ones on me}

It's my understanding the small tab on the master cylinder is removed so the banjo joint and brake line can be moved upwards, allowing further adjustment to the brake lever downwards {comfort etc}
You should check to make sure the brake light switch wires are not rubbing on the handlebars. They are the two tiny wires running out of the switchgear underneath. They can and will probably wear, and maybe short out.
Brake lights are important.
As for pads rubbing when hot, maybe time for a bleed.
Download the 6thGen manual for further details, as this can be quite a complex/frustrating/traumatic task.

Two things can cause this that I know of.  The first is an overfilled reservoir.  The second and more common thing could be a combination of things all revolving around the master cylinder piston not extending fully and not allowing the fluid to flow into the reservoir when it gets warm and expands.  It could be cause by "junk" in the master cylinder piston/seal area, or the lever could be bent and misaligned, not allowing the lever to move forward all the way.

Be absolutely sure you got a good bleed on the system (as per the manual) which includes the PCV cylinder under the seat.

I found that a My-Tee Vac bleeding tool is not enough to do the rear brake properly.  You have to depress the brake peddle at the same time you are drawing with the vac.

If the problems still is there it is time to replace the seals in the brake cylinders themselves.  I had this happen on my old ST1100 after cleaning the brakes with Brake Kleen.

It seems this fluid swelled the seals and even though the pistons were highly polished, once activated, did not like to pull back the fraction of an inch they are supposed to.  It led to destruction of the rotors before I figured out what the problem was.

All the problems I've had (bikes and cars) with brakes dragging usually came down to the slider pins not being greased properly.  I'd suggest getting some Synthetic brake caliper grease and lubing those pins up properly.  If they are all corroded you'll want to replace them first but hopefully they just need grease.

The pins are not binding up either.  What about the PCV valve?  I notice that brake fluid travels more readily one direction than the other through the valve, and the valve itself bleeds verrryy slowly.  Is this normal?  Would it cause the brakes to drag if the valve was faulty?

There was a recall on the PCV at some time. Here is the thread I remember...

6th Gen Rear Brake Failure, lost all brake fluid, need help fast from member Soichiro.

There should be a way of checking if the recall was performed. And I should add your brake symptoms are not exactly what was happening to Soichiro.

I am asking about the servo/proportional control valves because they are the last thing I can think that would be causing the problem.  M/Cs are good, seals are good, pistons are clean.  My question is whether these valves can cause a dragging brake situation.  If not, I know my problem has to be somewhere in the lines.

Now I have not only replaced the seals in the front calipers, but I am also running steel braided lines on the front, one from the front MC to each caliper.  Still the brakes are dragging.  SOmebody PLEASE help me out here!  School starts in a week and this fucking POS is my only ride to class.

[image: View Post]hycide, on Aug 10 2008, 11:54 PM, said:

They drag hard enough to stop the bike when the fluid gets hot. I have tried bleeding the system, checked front and rear master cylinders, cleaned pistons, "bounced" the front end, still dragging.

[image: View Post]slowf2337, on Aug 11 2008, 05:31 AM, said:

Two things can cause this that I know of.  The first is an overfilled reservoir.  The second and more common thing could be a combination of things all revolving around the master cylinder piston not extending fully and not allowing the fluid to flow into the reservoir when it gets warm and expands.  It could be cause by "junk" in the master cylinder piston/seal area, or the lever could be bent and misaligned, not allowing the lever to move forward all the way.
How did you "check the front master cylinder"?  That sounds like the problem to me.  As you mentioned it is obvious to you that the fluid is expanding due to heat.  That elimiates a bleeding issue (if there was air in the system it would compress that before locking your brakes).  The fluid has to be able to freely flow into the master cylinder reservoir when the lever is fully extended to allow for expansion.  All car and bike brake systems work like that.  I would try riding the bike until it feels like the wheel is locking up and then remove the front brake lever (take the locknut off before you ride) and see if it releases.  If that didn't release them try cracking the line at the master cylinder enough to relieve the pressure.

I remember reading in one of the motorcycle rags several years ago about this same problem when the brake fluid was warm.  It turned out to be an aftermarket brake lever that was causing the problem.  Something about the lever that did not permit the master cylider to properly bleed off the excess pressure as the fluid heated up.  I don't remember what kind of bike it was.

[image: View Post]Earthshake, on Aug 17 2008, 09:42 AM, said:

I remember reading in one of the motorcycle rags several years ago about this same problem when the brake fluid was warm.  It turned out to be an aftermarket brake lever that was causing the problem.  Something about the lever that did not permit the master cylider to properly bleed off the excess pressure as the fluid heated up.  I don't remember what kind of bike it was.

I think I read the same thing. It only takes a tiny amont for the brakes to not release.

My leak was not under the recall. A member was nice enough to help me out with a used part and it's been fine for 7k miles.

[image: View Post]hycide, on Aug 10 2008, 08:54 PM, said:

Just bought an 02 VTEC with 12000 miles.  The front AND rear brakes are dragging on the pads.  They drag hard enough to stop the bike when the fluid gets hot.  I have tried bleeding the system, checked front and rear master cylinders, cleaned pistons, "bounced" the front end, still dragging.  WTF?!?!  I did notice that the tab on the front master cylinder which holds the banjo bolt in place has been cut off at some point, not broken, but actually cut with a dremel or some other tool and filed smooth.  However, the MC itself looked good, no blockages or boogered seals.  What do I do next?!?  Replace the master cylinder?  Leave the bike downtown with the keys in it?
Welcome!

i read the thread and just about everything has been covered but the pads themselves. if the pads had just been changed and they were not the correct thickness or even the wrong part number this alone could cause the problem. you could buy and install a set of stock pads, but the one check i would do first is slip a putty knife or something similiar between the pad and the rotor (forcing piston back into the puck hole). after having done this on all the pads the wheel should turn with NO drag. i put a set of wave rotors on the front of my y2k. these were the early style that you couldn't use HH pads. tried to install new factory pads and they were too thick. i put the HH pads on and had lots of clearence (yeah, and they are eating the rotors, i should have returned them for the plus rotors. maybe next time!). :pissed:

I know on the 5th Gen the Manual makes a big point of mandating a .7mm gap between the caliper and the rotor.  Not sure about the 6th Gen, but you could check.  If the gap is required and not there, the caliper will be too close to the rotor and it will drag the pads.

Also, I don't know if the lever has a screw adjuster that adjusts contact with the m/c, but if it does, be aware that some people "modify"' their braking by adjusting that screw for "quicker" contact.  What happens is that the brake fluid gets warm, expands, and pushes the m/c piston out to where it contacts the adjustment screw in its "modified" position.  If there's not enough room for the expansion, it's the same as keeping the brake applied.  Some have actually locked the front brake once the fluid gets warm enough.

Anyway, just two more things to check.

Also, I'm sure you're aware that no disk brake system is completely drag-free.  Some drag is normal and always present.  It should require some effort to spin the wheel 1.5-2 times (hard to get more out of it than that, due to the drag).  If it's stopping almost immediately, however, that's not normal.

More speculation:

Did you bounce the front end, with the pinch bolts loose?
Are the axle spacers on the correct sides? USUALLY, it will cause the tire to bind, completly. But if the axle bolt is not flush to the right fork, that may be a clue.

I know you are bombarded with a lot of things to check, but with VFRD, you'll get it.

check for some free-play at the brake lever

[image: View Post]Earthshake, on Aug 17 2008, 09:42 AM, said:

I remember reading in one of the motorcycle rags several years ago about this same problem when the brake fluid was warm. It turned out to be an aftermarket brake lever that was causing the problem. Something about the lever that did not permit the master cylider to properly bleed off the excess pressure as the fluid heated up. I don't remember what kind of bike it was.

The aftermarket lever for my 99 was like that.  I had to grind down the part of the lever that touches the pin in the master.  I could not get to the end of the street without the brakes starting to apply.

Stock pads or EBC HH? Did the previous owner do a change? How may miles have YOU put on the bike?

How bad are they dragging?  Some touching is normal as the pads wont come off the rotors 100%.  If its just noise I think you are trying to cure something that is normal.  If you spin the wheel and it stops half way around then you may have an issue and still think its the master cylinder...

I checked the front MC by disassembling it and inspecting the seals, spring, and piston.  Everything looked like new.  The main and return ports were also clear, and I double checked this by blasting them with compressed air.  

I removed the brake lever completely, but even with the fluid now cool and the bike at rest, the brakes are still dragging enough to cause the wheel to stop after 1/2 turn or less.

Removing one caliper will free the wheel up considerably, the funny thing is, at one point it was the right caliper that was binding, now since I changed lines it seems to be the left caliper.  I don't think it has anything to do with alignment tho.  I placed a steel shim about the same thickness as the rotor between the pads, and squeezed the brakes so the pads would pinch it.  Once the brake lever is released, the caliper continues to hold onto the shim, taking some effort to remove even when cold.

Another point of interest is that I have rotated between the pads that were on the bike and a new set of EBC HH pads (stock rotors), and the problem persists with either pad.

[image: View Post]Misspent Youth, on Aug 17 2008, 08:56 AM, said:

I know on the 5th Gen the Manual makes a big point of mandating a .7mm gap between the caliper and the rotor.  Not sure about the 6th Gen, but you could check.  If the gap is required and not there, the caliper will be too close to the rotor and it will drag the pads.

Also, I don't know if the lever has a screw adjuster that adjusts contact with the m/c, but if it does, be aware that some people "modify"' their braking by adjusting that screw for "quicker" contact.  What happens is that the brake fluid gets warm, expands, and pushes the m/c piston out to where it contacts the adjustment screw in its "modified" position.  If there's not enough room for the expansion, it's the same as keeping the brake applied.  Some have actually locked the front brake once the fluid gets warm enough.

Anyway, just two more things to check.

Also, I'm sure you're aware that no disk brake system is completely drag-free.  Some drag is normal and always present.  It should require some effort to spin the wheel 1.5-2 times (hard to get more out of it than that, due to the drag).  If it's stopping almost immediately, however, that's not normal.
To continue, your left side caliper which continues to drag is the one the 5th Gen manual says has to have the .7mm gap.  You adjust the gap by moving the forks in or out with the axle loose.

Your PO dremeled the front line to rotate it - it's possible he modified the lever and pedal so they make excessive contact with the m/c.  I'd suggest removing the brake pedal and front lever from the equation by removing them from the bike and seeing how tight things are then.

On the linked system, excessive LEVER pressure won't send pressure to the rear caliper, but excessive PEDAL pressure will send pressure to the front, and it will send it to the left caliper first, due to the PCV function.  I'd look harder at the rear m/c and pedal.

Just replaced pads from stock to EBC HH and a fluid flush and now I have the same problem.  

I made sure to thoroughly clean the exposed portion of the pistons before shoving them back into the caliper since that has caused me terrible problems in the past.  

Things have impoved after multiple flushes and re-seating of the pistons, but still not as they should be.

I'm going to run them at the track tomorrow (keeping a close eye, ear and nose on them).  If I have to shut down early, so be it.  Otherwise, I'll tear 'em all apart after that to check all the ports, seals, pistons, etc.

i am sure you wouldn't do what i did, but just bought 3 packs of FA261 pads off ebay.  two of them were fa261/hh pads.  one was a fa261/2hh pad.  i thought they were the same....they are not.  the 2hh is thicker padding and will drag on your rotor.

Lee,

YOUR problem is prolly that you need to take the shims off the pads, for about 1,000 miles. EBC made the pads too thick, and with the shims in,.....BIND.

[image: View Post]Rivcyko, on Aug 18 2008, 03:54 PM, said:

Lee,

YOUR problem is prolly that you need to take the shims off the pads, for about 1,000 miles. EBC made the pads too thick, and with the shims in,.....BIND.
i just put in HH pads 500 miles ago and no problems....

I know it sounds like blasphemy, but if you're under a really tight deadline, you could consider taking the bike somewhere you trust and having them look at it.  I just replaced my pads with EBC HH pads, and there was a shim on the non-piston side of the fronts and shims on both sides in the rear.

Now that i think about it, the shims were on the stock pads, but did not come on the EBC pads. I washed and transfered them to the new pads - I hope that's OK! I do hear them dragging very lightly when i spin the wheel, but it spins a few revolutions before it stops, and didn't have any issues when i rode it.

I didn't understand the .7mm clearance thing even after reading it in the manual. I'll have to go look at it again to make sure I didn't F* something up.