do I need a new brake master cylinder? [update]

[martin_14]

I changed my old brake discs, all 3 of them, for EBCs with the corresponding pads. After a thorough test through the Italian Alps the last 10 days (I did around 2000 miles), I can say that there seems to be no difference on the braking power, but there's noise and, at some lever pressure levels, vibration It seems like this magic button design between disc and hub has some play, not sure. This is changing, I guess due to the pads seating on the discs, but so far I'm not exactly thrilled with the vibrations. As I said, the noise doesn't bother me, and I knew it was going to be there because nearly everybody going to EBCs mentioned it, and I run my second set of OEM discs (the first ones where changed under warranty due to warping) with EBC pads and they were noisier than stock pads.
So, that's the story on the brake discs. But what triggered me to change them was the spongy feeling on the lever on first pulsation, which after quick release and re-applying force, the lever became stiff again, as it used to be before this issue started. There's no air in the system, or at least it's been bled thoroughly a couple of times. So, my mechanic thinks that after 70 000 miles the piston sealing in the brake master cylinder might need replacement (50 dollars), or maybe the whole assembly (316 dollars).
Has anybody had to deal with this? what was the symptom, and the solution?
I have been dragging on this issue with the brakes for some time and I want to get on with it. I take fanatical care of the bike, but sometimes I ride hard, two up, and I punish the bike when some wannabee on a crotch rocket wants to show off.

PS: this bike really packs a punch. I had the chance to measure her against a Triumph Rocket III and, although that thing has torque, it also has mass and lack HP. In the right gear, I could easily keep up, and even go quicker. So far, only a well ridden Panigale or the likes are able to pull away in the Alpine passes. And some smart old f@rt on a prehistoric Yamaha Diversion 900, whose name I won't mention (Rick)

[VirginiaJim]

Something uneven is causing the lever to become soft and then hard.  The only time I had that happen to me was when one of the front rotors warped.  But it could also be a worn master cylinder or caliper letting air into the system.  When you finish riding for the day, make sure the lever is where it should be and then check it in the morning.  If its soft again by just sitting then it's a worn cylinder or caliper piston seal.  I don't think a pad deposit can affect the lever (it might affect vibration though).  You need to get the rotor checked for warpiness.  Check the pads and see if you see any uneven wear on them.  That can be an indicator.

[harry76]

I also got a new set of EBC brake rotors, and after installing had a pulsing and vibration in the brakes.
I Measured the rotors and found 5 thousands of an inch difference at various points on them.
I called EBC and they sent me new ones but I haven't even opened the box yet.

[B.D.F.]

As far as the spongy lever that gets hard on the second pull (Easy Boys!), I believe that is due to air in the system. C-14's are horrible to bleed and I have not had any success fully bleeding any of the three hydraulic systems without a power bleeder. I could get 95% of the way there but that last little bit of air was really elusive and resistant. A MityVac power bleeder pulls fluid through the system fast enough to get ALL of the air out of the system in my experience.

This has nothing to do with the pulsation though, that would be some variable in a rotor (or both).

Brian

I changed my old brake discs, all 3 of them, for EBCs with the corresponding pads. After a thorough test through the Italian Alps the last 10 days (I did around 2000 miles), I can say that there seems to be no difference on the braking power, but there's noise and, at some lever pressure levels, vibration It seems like this magic button design between disc and hub has some play, not sure. This is changing, I guess due to the pads seating on the discs, but so far I'm not exactly thrilled with the vibrations. As I said, the noise doesn't bother me, and I knew it was going to be there because nearly everybody going to EBCs mentioned it, and I run my second set of OEM discs (the first ones where changed under warranty due to warping) with EBC pads and they were noisier than stock pads.
So, that's the story on the brake discs. But what triggered me to change them was the spongy feeling on the lever on first pulsation, which after quick release and re-applying force, the lever became stiff again, as it used to be before this issue started. There's no air in the system, or at least it's been bled thoroughly a couple of times. So, my mechanic thinks that after 70 000 miles the piston sealing in the brake master cylinder might need replacement (50 dollars), or maybe the whole assembly (316 dollars).
Has anybody had to deal with this? what was the symptom, and the solution?
I have been dragging on this issue with the brakes for some time and I want to get on with it. I take fanatical care of the bike, but sometimes I ride hard, two up, and I punish the bike when some wannabee on a crotch rocket wants to show off.

PS: this bike really packs a punch. I had the chance to measure her against a Triumph Rocket III and, although that thing has torque, it also has mass and lack HP. In the right gear, I could easily keep up, and even go quicker. So far, only a well ridden Panigale or the likes are able to pull away in the Alpine passes. And some smart old f@rt on a prehistoric Yamaha Diversion 900, whose name I won't mention (Rick)

[martin_14]

thanks guys. Out of the country now, but coming back this weekend. On Monday I'm taking her to the dealer and getting the discs and master cylinder checked.

[VirginiaJim]

Let us know how it turns out Martin.

[martin_14]

will do. But crappy weather has kept me from riding the whole week so no trip to the dealer yet.

[martin_14]

so, I managed to drive to the workshop. All seals (front brake callipers and master cylinder) are going to be exchanged. He'll order the parts and I got a slot for next week. I hate my brakes right now. I'll report back when the job is done.

[martin_14]

so, yesterday I picked up the bike. Things are back to normal, it seems. They redid the callipers and master cylinder (disassembled, cleaned and changed the sealings) and the piston on the master cylinder has been changed, as well.
The lever seems to have a consistent travel and the amount of force I have to apply for a given braking effect is also immediately there, no need to "prime" it by squeezing it, letting go and quickly apply brakes again. I'm still skeptical, I must say, but if this stupid weather let's me go out for a spin I'll be able to check if the problem is really gone.

Side note: for the 24 hs that the bike was in the shop I got a Versys 1000 fully equiped (extra lights, gear indicator, side and topcases...). I really liked it, very very comfy, until I braked. Bike had just 500 miles and the discs were warped beyond words. On the positive side, the engine was surprisingly smooth, more so if we consider that it has just one balance shaft. Very unlike the buzz that I remember from the Z1000SX when it came out and I considered it as a replacement (NOT!!!) for my 1400GTR.

[update]
the amount of force I have to apply on the brake hand lever, and the travel I get, are now consistent. Good.
The braking force is rubbish. Bad. It means that I have to squeeze the brakes quite a bit in order to stop the bike. Not happy. I'm going back to the workshop on Monday to see what can be done. Not happy right now.

[martin_14]

instead of going back to the shop I decided to leave it as it is (bike brakes, after all) and go on a trip to the south of France (yes, I was 50 miles from Nice when the shite happened).
After just 500 miles or so, and probably due to extreme heat (100°F), passenger and fully loaded, the brakes went back to the previous bad behaviour. I'm NOT amused. After that I drove another 3000 miles through the Alps to Slovenia and back to Munich yesterday evening, some 1000 miles alone but spirited. Bike delivered, but I have to first squeeze the lever so the calliper pistons push the pads against the discs, then release and reapply pressure quickly to start the braking itself. While I was in France I found a really good Kawasaki dealer that bled the system (found air on the left front part of the system) and the guy told me that either the brakes have to be rebuild (they just have been) or the seals are still stiff and keep pulling back the pistons too far into the calliper when I let go the lever. He added that it should get better with the mileage, but 2000 miles later it hasn't.
I'm pissed. I'm going to see my mechanic at some point in the next days, but I'd like to have your input, guys, from those that know about the matter. PLEASE!!!

[gPink]

Martin, as a temporary fix try pumping the lever and tying it back to the handle overnight. If it's the seals sticking to the pucks they should release and return.

[martin_14]

Martin, as a temporary fix try pumping the lever and tying it back to the handle overnight. If it's the seals sticking to the pucks they should release and return.

gPink, thanks for the reply. I did pull the lever and tied it overnight during the trip, a few days after the bleeding procedure was performed, because it was still requiring a pre-pumping of the lever. Yes, it felt a bit more "solid" the next day, but the pre-pumping action was still required. All this leads me to think that the air is not the problem, and the bleeding will only address the sponginess pressing the lever (which is not much), but it still seems to me that the problem is the pistons being pulled back into the calliper, hence the need to "pre-pump". Please correct me if I'm wrong.

A question (it's my English): could you explain me what you mean with "puck"? is it synonym of "piston"?

Another one: how far can I pull the brake lever? until it touches the handlebar? it seems like a big amount of force...

[gPink]

Piston=puck...same thing. Still sounds like air in the system. Does altitude make any difference? Softer up high....firmer at lower levels?

[B.D.F.]

As I said before, I have found C-14's virtually impossible to bleed by hand and it even takes a surprising amount of time and brake fluid using a power bleeder. These hydraulic systems really hate to let go of that last little bit of air. My suggestion would be to find a place that will power bleed the brakes and clutch, and pay them extra to do it at least twice as long as they think is required. Put another way, pay them to bleed the entire hydraulic system twice and if at all possible, watch them do it.

Once these systems are properly bled and completely free of air, they feel like a mechanical linkage (which hydraulics really should feel anyway). Otherwise, they remain somewhere between a bit spongy all the way to needing a few strokes (Easy Boys!) to pump them up (Boys!).

Brian

<snip>


I'm pissed. I'm going to see my mechanic at some point in the next days, but I'd like to have your input, guys, from those that know about the matter. PLEASE!!!

[martin_14]

thanks, guys. I'm starting to buy the "still needs a proper bleeding" explanation. I know that this is an uncommon bike compared to 600s and litre bikes, and as Brian said, extraordinarily difficult to bleed thoroughly, but my dealer should be aware of this and, believe me, my bike does not feel like it should.
While I was waiting for the job to be done I had a walk through the show room, which included even a H2 and an H2R, I sat on a new GTR1400 and the brakes were amazing. That made me so angry... I don't see a reason not to have that feeling in my bike at the first brake lever pull, not the second or third. I understand that the lines are old, of course, and that adds flexibility to the system, but what I feel in my bike seems to me different than just sponginess.
Anyway, keep thoughts & knowledge coming, please. I still have a few days till I put the next 700 miles for the service at the dealer.

PS: I'm considering the purchase of a brake bleeder. Any suggestions? I can't do a search here in Germany because I don't even know the name of these things in German 

[gPink]

https://www.amazon.com/Mityvac-MV8000-Automotive-Test-Bleeding/dp/B00265M9SS

https://www.amazon.com/Mityvac-6830-Brake-Bleeder/dp/B000JFN9WC

Two examples....

[maxtog]

And what I bought but haven't used yet:  http://www.motionpro.com/product/08-0143

[B.D.F.]

Not knocking that product at all but that is not  a power bleeder. It is simply a check valve and still requires the old 'pump and squirt' (Extra Easy Boys!) to bleed the brakes.

Power bleeders are usually powered by compressed air (using what is called a vacuum aspirator) or electricity.

Brian

And what I bought but haven't used yet:  http://www.motionpro.com/product/08-0143

[maxtog]

Not knocking that product at all but that is not  a power bleeder. It is simply a check valve and still requires the old 'pump and squirt' (Extra Easy Boys!) to bleed the brakes.

Power bleeders are usually powered by compressed air (using what is called a vacuum aspirator) or electricity.

That is extremely true, but I was just responding to "PS: I'm considering the purchase of a brake bleeder. Any suggestions?"  He didn't specify a power bleeder, just a "bleeder".  I can't really even recommend what I have, since I have never used it yet    But it is something to consider, especially on the cheap.

[lather]

I use the motion pro check valve bleeder for all my bikes and cars. It works great fro me, the Concours brakes and clutch are no problems with it. It even works on Honda linked brake system, which otherwise takes 5 arms an 7 hours hours to bleed.