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

[tjhess74]

I changed the pads on my rear brake a couple of weeks ago with a set of EBC's.  I too now have noticeable vibratory feedback in the lever and there is also some sponginess.  After about 400 miles, I bled the rear brake, even though no air can get introduced simply from changing pads, but to no avail.

I've only used Galfers and OEM to this point, and I may go back to them soon and write off the cost of the EBC's. I'm not sure what would be different about a brand name pad that would cause this.

[PlaynInPeoria]

I run EBC HH's on everything, never an issue. I have them on C14 now.

[VirginiaJim]

+1, no issues.

[martin_14]

I have EBC discs all around and HH EBC pads. No idea if that's the issue, but I don't think so. It's somewhere between master cylinder and brake calliper 

Oh, and I forgot to mention that when I asked about a brake bleeder, I meant power bleeder. Sorry!

[cmoore]

I'll chime in on the EBC pads. I have them on the front stock discs with no issues. I have a non abs '10 that I've successfully bled in the past.

[martin_14]

I haven't used the bike for a week (too busy at home), so yesterday when I went for a ride I was curious about the brakes. Unfortunately, they were not only still needing a pre-pump action to bring the pads in contact with the disc before actually doing and braking, but they were also mushy. Like if the lever was pulling a shoe-string instead of an expensive braking system. Drat.
So I spoke with a friend who is actually a mechanic (albeit cars) and is on his umpteenth bike, and after good consideration and diagnosis process suggested that, before changing the master cylinder, actually change the brake lines, with steal ones, if possible. The bike has almost 75 000 miles of a lot of sporty driving (Alps), so lots of heavy braking, so they are due anyway. I have the money for it, and I don't want to skimp on this.
I'll go talk with my mechanic today and see what he thinks. I really like the bike and I can't afford selling it (with that mileage I won't get anything for it) and getting another, "younger" one.

[jonathan]

New brake lines will not fix the need to pump the brakes. Somewhere there is air getting into the system. If it has been bled so that it feels like new and is now mushy again then the seals should be checked. If it hasn't been properly bled then try that first.

[martin_14]

hi Jonathan, thanks for the concern and advice.
I agree with you that somewhere there's air getting into the system, but bleeding it didn't help this symptom. It just felt a tad more solid, and the biting point was a bit more consistent. As soon as I used the bike for a few minutes, the need to pump is there. It was bled several times by different people, and the need for pumping keeps showing up.
I just came back from talking with the mechanic and I'm taking the bike in on Tuesday. I told him to keep it a couple of days and use it, go home if he wants to, so he gets the proper picture of what's going on. The lines are old (almost 9 years since the bike's been put together in Japan) and it's been used, believe me. I wouldn't blink if somebody told me "hey, time to change your brake lines". So I'll go with steel lines no matter what. BTW: should I pay extra for the stainless steel fittings, or are aluminium fittings alright? what material are the OEM fittings?
Anyway, I hope that's it, but I made it clear to them that if I'm going to cough that sort of money on the brakes, I want them sorted out.

[martin_14]

so, bike's at the dealer getting stainless steel braided brake lines, new tires, and an oil change. ABM GmbH, the company that bought a good German manufacturer of brake lines some years ago, sent the bike specific kit with a couple of bits (10 lines in total) wrong, and the new (hopefully correct) parts will arrive on Tuesday 
The mechanic said that in order to do it calm and thoroughly he'll need at least a day so he can test everything. A ton of tupperware had to come off, too. So he predicted that the bike should be ready for collection on Thursday. I can't wait to feel the difference, if there's any. I drove plenty of bikes with steel braided lines and I always loved the solid feeling when applying the brakes, but I also loved the powerful brakes on the C14. Let's see...

[gPink]

 

[VirginiaJim]

Would the stock lines have been less expensive, Martin?

[martin_14]

Would the stock lines have been less expensive, Martin?

well, I honestly don't know, but the steel lines cost around 300 and the work is the same, so I thought "let's do it". Based on what I saw with the OEM brake discs and the EBC, which cost half, I'd say that I would have paid the same, but I'll ask when I pick up the bike and get back to you with that one.

[VirginiaJim]

So far I haven't had any issues with the stock brake lines but when you have issues like you've had, it's darn difficult to narrow down what exactly is causing the problems.

[martin_14]

little feedback. Today I finally picked up the bike. When I arrived at the dealer, the owner was serious. He told me that there were two issues still to solve.

1st the good: the steel lines have been installed and there's a solid feeling on the lever.

Now the bad-then-good-so...-neutral: the rear brake disc, which I got from EBC a couple of months ago and had installed, is around 20mm (3/4") too small in diameter, so the brake pads are only used in the inner half (I've got to get a picture). Although it was sent wrong, the dealer admitted that he should have noticed and will pay for the new rear brake disc and install it.

The second bad: the front right brake disc, also EBC (XC, with the golden hub) is warped by 0.4mm. Kawasaki states 0.2mm as still acceptable, 0.3mm being the maximum allowed. I believed that I drove them kindly.

So I just sent an e-mail to the vendor (it was through Amazon here in Germany) to ask about an exchange. I also sent an e-mail to EBC in the UK because the mechanic and I were inspecting the assembly and noticed that the golden hub of the EBC disc is actually 6mm think, when the original is just 5mm thick. The consequence is that on the right side, the ABS sensor rubs on the ring, which screws on top of the brake disc.

So, summarising: the rear disc was too small, and from the two front discs, one was warped, and they are too thick. I'm not happy right now.

[maxtog]

summarising: the rear disc was too small, and from the two front discs, one was warped, and they are too thick. I'm not happy right now.

Yeah, that sucks... I wouldn't be very happy either.  But it is nice that you have a good dealer working with you on this stuff.  I hope it works out...

[gPink]

Would the warped disc contribute to the soft feeling (easy boys) that you've been having?

[VirginiaJim]

Depends on the warp, but yes it can and does, at least it did with me.

[martin_14]

Yeah, that sucks... I wouldn't be very happy either.  But it is nice that you have a good dealer working with you on this stuff.  I hope it works out...

Thanks. Yes, it's a good dealer and it's only the third time that they do a mistake, although the other 2 times was some triviality like a delayed spare part or something. I've been with them for 7 years and 60 000 miles now, and we are humans and do mistakes, it's ok. But the way they always fix it is what I like from them. They even wash the bike when they have the time.

Would the warped disc contribute to the soft feeling (easy boys) that you've been having?

well, the soft feeling is gone, now the lever feels solid, for which I'm pleased. But the difference in biting point is still there. I first need to pull the lever in order to bring the pads against the disc, and a quick release-pull of the lever will really brake the bike. What changed now with the steel lines is that the second pull applies the pressure so sharply, that the ABS comes on easily, so I had to back off a little with how hard I pull that second time.
Yesterday the mechanic put a very thin (0.5mm or so) washer under the ABS sensor in order to avoid it rubbing on the sensor ring. As a result, on my 200 miles ride today I noticed that all rubbing noises from the front wheel area disappeared, which is very nice. Even the discs don't seem to rub on the pads when I'm not on the brakes, as it has to be. Good. Another thing I noticed is that when gently applying the brakes while coming to a stop like on a crossing, the braking force remains constant during the whole complete turn of the wheel, meaning that whatever warping is there, it's mild enough for the floating part of the assembly to cope with it. And yet, it's significant enough to push the pads away and giving me that dead stroke on the lever after a few seconds. Annoying.
Meanwhile, the vendor ask me to send him the disc for measurement and eventually a refund. I'll send it, but I just ordered another disc and pads so there's no downtime on the bike. It should be here by Tuesday... fingers crossed.
For now, I'm enjoying this bike as usual. Apart from the steel brake lines it got new tires (Pilot Power 3), oil, spark plugs and air filter. She sings and rides and overtakes. And today on my way home I passed the 120 000 km milestone. That's around 78565 miles

[VirginiaJim]

You shouldn't have to pull the lever twice to get the brakes to work or am I misunderstanding what you are saying?

[martin_14]

It does brake, it just has a bit of a dead stroke before actually engaging. And that dead stroke changes, depending on where are the pads in that moment  Frustrating.
I just went out with the bike to meet some friends, and on the way back I turned off the engine to check if it really is silent on the front of the bike. It isn't, and I think now it is the disc rubbing on the pads at a certain position of the wheel, once every rotation. I just cannot tell if it is the right or the left, but tomorrow I'll put the bike on the centre stand with my girlfriend on the rear seat and will check.