Author Topic: Am I bleeding the rear brake wrong?  (Read 1956 times)

Offline okrider

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Am I bleeding the rear brake wrong?
« on: August 05, 2018, 10:40:48 am »
Hey folks, I have a 2011 C14. Back story. Bled my brakes (front & rear) when I got the bike about 2k miles ago. I pressure bleed without any fancy vacuum tools because it has worked for me in the past and still works. However, I have been upset with a dead spot at the beginning of the rear brake. I just thought it was how it is on this bike with the linked brakes.

Last week, while reading up on the bike, noticed that there's two bleeder valves on the rear brake. I just went and bled the inner (facing the wheel) nipple and sure enough, some dark fluid came out. Brake feel however, hasn't changed. There's still about an inch of empty travel on the brake pedal. Is this how this bike's brakes are? or am I doing something wrong.

Is one of the valves connected to the front brake?

Please don't tell me to buy a brake vacuum thing, I've had horrible luck with those and almost always ended up letting air into the system somehow. Just trying to learn how the braking system works.
'11 Black: Russel Day-Long, Mountain Runner, cage w/ highway pegs, 2Bros Slip-on, Helibars Horizon

Offline okrider

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Re: Am I bleeding the rear brake wrong?
« Reply #1 on: August 05, 2018, 11:31:12 am »
Just confirmed that the rear brake caliper is not attached to the front brakes in any way. Clear fluid coming out of the rear caliper now but there's still a dead zone at the beginning of the pedal. Going to try to leave the pedal pressed overnight, see if any air makes its way out.
'11 Black: Russel Day-Long, Mountain Runner, cage w/ highway pegs, 2Bros Slip-on, Helibars Horizon

Offline jwh20

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Re: Am I bleeding the rear brake wrong?
« Reply #2 on: August 06, 2018, 08:13:26 pm »
No "dead" spot on either of the C14's I've owned.  Neither my non-ABS 2008 nor my ABS 2012 had this.  The usual symptom of air in the lines is "sponginess" that is especially noticed as you build pressure and not when you first apply vs. what you're describing.

I think the first thing I'd check is the linkage on the rear master cylinder as well as the brake line itself.

Offline maxtog

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Re: Am I bleeding the rear brake wrong?
« Reply #3 on: August 06, 2018, 09:00:52 pm »
 :goodpost:

I can't comment much about the rear brakes, since I never [manually] use them.  But my understanding is air would normally be sponginess, not usually an engagement gap.
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Offline okrider

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Re: Am I bleeding the rear brake wrong?
« Reply #4 on: August 06, 2018, 09:08:22 pm »
I will examine the rear brakes tomorrow. What I noticed is that "dead spot" disappears if I'm applying the front brakes. It is only noticeable when I want to rear brake only. I'm going to be doing rear brake only all day tomorrow to try to understand how it works. I'll also take a closer look at the pedal and master to see if there's a gap or something in the pedal before it engages. I'll post my findings. Thanks for the replies.
'11 Black: Russel Day-Long, Mountain Runner, cage w/ highway pegs, 2Bros Slip-on, Helibars Horizon

Offline maxtog

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Re: Am I bleeding the rear brake wrong?
« Reply #5 on: August 07, 2018, 12:47:27 am »
I'm going to be doing rear brake only all day tomorrow to try to understand how it works.

Well, you may be activating only the rear, but as you know, you won't actually be using only the rear :)  If experimenting, make sure to try both the high-linked and low-linked settings.
Shoodaben (was Guhl) Mountain Runner ECU flash, Canyon Cages front/rear, Helibars risers, Phil's wedges, Grip Puppies, Sargent World seat-low & heated & pod, Muzzy lowering links, Soupy's stand, Nautilus air horn, Admore lightbar, Ronnie's highway pegs, front running lights, all LED, helmet locks, RAM Xgrip, Sena SMH10, Throttle Tamer, MRA X-Creen, BearingUp Shifter, PR4-GT, Scorpion EXO-T1200,etc

Offline Freddy

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Re: Am I bleeding the rear brake wrong?
« Reply #6 on: August 07, 2018, 01:33:19 am »
Just confirmed that the rear brake caliper is not attached to the front brakes in any way. Snip> 

It is via the ABS unit in both 'directions' like Max says - that's why you notice this: What I noticed is that "dead spot" disappears if I'm applying the front brakes. It is only noticeable when I want to rear brake only.     

https://www.kawasaki.ca/media/mig/2012/concours-14-abs/English/files/assets/downloads/page0007.pdf
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Offline okrider

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Re: Am I bleeding the rear brake wrong?
« Reply #7 on: August 07, 2018, 06:59:05 am »
It is via the ABS unit in both 'directions' like Max says - that's why you notice this: What I noticed is that "dead spot" disappears if I'm applying the front brakes. It is only noticeable when I want to rear brake only.     

https://www.kawasaki.ca/media/mig/2012/concours-14-abs/English/files/assets/downloads/page0007.pdf

I meant as far as bleeding it goes. I tried pulling the lever in while bleeding the rear, the lever didn't budge. I know that air sometimes gets trapped behind the pistons in the caliper and doesn't come out, especially since this is a hanging caliper. I'm going to push the rear brake pistons in today, forcing any air out. If that doesn't work, I'll adjust the pedal lower so the dead spot is gone, making sure I"m not constantly braking.

There's a good chance what I'm experiencing is spongy brakes until the front kicks in as well. I just went outside and checked it out and I'm pretty sure it's spongy. Going to get all that air out today. Tell me if I'm doing the bleeding wrong.

* Check to see fluid level is above "Low". Refill if necessary.
* Pump the rear brake pedal a couple times and keep it pushed down
* Open the bleeder valve for a second and close it
* Observe fluid moving out
* Repeat
« Last Edit: August 07, 2018, 07:36:13 am by okrider »
'11 Black: Russel Day-Long, Mountain Runner, cage w/ highway pegs, 2Bros Slip-on, Helibars Horizon

Offline kzz1king

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Re: Am I bleeding the rear brake wrong?
« Reply #8 on: August 07, 2018, 03:03:05 pm »
I think you will find that using a vacuum bleeder is a preferred method. These things can be tough to bleed. I bought one from Harbor Freight for very little money and it really made the job of changing the fluid a lot easier.
Wayne
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1974 Z-1

Offline okrider

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Re: Am I bleeding the rear brake wrong?
« Reply #9 on: August 07, 2018, 04:46:39 pm »
Just tried pushing pistons in, followed by bleeding the rear brake again. No difference. There is still dead spot where there is no braking force at the beginning of the pedal travel. The fluid coming out is clear with no bubbles. Not sure what else to do right now. Also tried adjusting the pedal on the master cylinder. This had no effect either.
'11 Black: Russel Day-Long, Mountain Runner, cage w/ highway pegs, 2Bros Slip-on, Helibars Horizon

Offline Freddy

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Re: Am I bleeding the rear brake wrong?
« Reply #10 on: August 07, 2018, 05:18:14 pm »
Hey folks, I have a 2011 C14. Back story. Bled my brakes (front & rear) when I got the bike about 2k miles ago. I pressure bleed without any fancy vacuum tools because it has worked for me in the past and still works. However, I have been upset with a dead spot at the beginning of the rear brake. I just thought it was how it is on this bike with the linked brakes.

Last week, while reading up on the bike, noticed that there's two bleeder valves on the rear brake. I just went and bled the inner (facing the wheel) nipple and sure enough, some dark fluid came out. Brake feel however, hasn't changed. There's still about an inch of empty travel on the brake pedal. Is this how this bike's brakes are? or am I doing something wrong.

Is one of the valves connected to the front brake?

Please don't tell me to buy a brake vacuum thing, I've had horrible luck with those and almost always ended up letting air into the system somehow. Just trying to learn how the braking system works.

You nailed it in the first post.
The best substitute for brains is .............what?

Offline okrider

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Re: Am I bleeding the rear brake wrong?
« Reply #11 on: August 07, 2018, 05:41:21 pm »
You nailed it in the first post.

So that's just how it is? I just came home and ziptied the front brake lever pulled in, put a rod on the rear pedal and propped it open. Going to leave it like this overnight, see if there's any changes. If not I'm caving and buying a pressure vac.
'11 Black: Russel Day-Long, Mountain Runner, cage w/ highway pegs, 2Bros Slip-on, Helibars Horizon

Offline okrider

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Re: Am I bleeding the rear brake wrong?
« Reply #12 on: August 08, 2018, 08:26:41 am »
Just bit the bullet and bought a brake bleeder. I do hate the hand pump style so went with the pump with the container. It definitely costs way more but I've used one before and love them.
'11 Black: Russel Day-Long, Mountain Runner, cage w/ highway pegs, 2Bros Slip-on, Helibars Horizon

Offline Tree

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Re: Am I bleeding the rear brake wrong?
« Reply #13 on: August 08, 2018, 08:52:38 am »
Look at Speed Bleeders.  They replace the stock bleed screw with one that has a check valve (ball bearing).  Super easy to install and use.  It makes bleeding brakes a breeze on the bike.  They make them for cars & trucks too - check it out.

2 for the front brakes (1 each caliper)
2 for the rear brakes
1 for the clutch
1 for the front master cylinder
1 for the clutch master cylinder

http://www.speedbleeder.com/

You can use the vacuum pump if you want to but you might find that you don't need it if you install Speed Bleeders.
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Offline kzz1king

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Re: Am I bleeding the rear brake wrong?
« Reply #14 on: August 08, 2018, 10:13:15 am »
 I had never used the vacuum pump before. Picked a cheap one up at HF. Brakes didn't need bleeding but I changed fluid with it. Barely cracked the bleeder .th He had had a lever that holds it on so I just watched and added fluid. Quick and easy. Cheaper than the speed bleeder too if you use it on more than one vehicle.
Wayne
2010 CONCOURS
1974 Z-1