View Full Version : Rear Brake Bleedout?


JBinSD
March 27th, 2013, 02:10 PM
So I did my front SSBL today, and changed my rear tire, and checked my rear brake, and like almost nothing, full pedal travel, and no pressure. The routing of the OEM brake line does a little roller-coaster up and down, and putting on Vortex rearsets raised the cylinder another couple inches.

To be honest, I don't know if I've ever had a back brake, since I never use it, but now I'm pissed. I re-bled the line about 6 times, and it would hold pressure when the caliper was off and on an equal level with the resevoir, but would lose pressure when its bolted on the caliper perch. Wtf?

I'm going to switch out the rear line with SS tomorrow morning before hitting the track, but have any of you had this problem? I'm bleeding from both the bleeder value and the banjos trying to get rid of any air, but each time I get pressure built up, I bolt on the caliper and whoosh, pedal travel with no pressure.:(

Fookin weird, I'm hoping the new line will solve it, but wanted to see if anyone else had a similar experience or advice.

thanx,
Joel

rojoracing53
March 27th, 2013, 02:30 PM
You have to be missed something in the equation but from your description I can't say what.

geeker
March 28th, 2013, 05:45 AM
Are you using the brake light switch with the rearsets? When I put in new tires, I noticed a little seepage from the fitting between the rubber hose and the caliper banjo. I never lost pressure though. They still work like the day I took delivery of it.

Joshorilla
March 28th, 2013, 05:59 AM
Hmm, so you're bleeding the caliper off the bike "raised up I hope"? Are you using a piece of wood simmilar thickness or slightly thicker to your disc between your pads? Obviously air is getting in somewhere, either you havn't got it all out or more in being introduced somewhere, this could be the banjo bolt crush washer gap or the piston seals on the calipers, or simply you havn't let it all out and it's retained in the line, do the pistons and seals look to be in good condition? And is the banjo bolt tightened to spec "no too tight as it's aluminium!"?

Motofool
March 28th, 2013, 06:27 AM
May it be a defective master cylinder?

http://upload.wikimedia.org/wikipedia/commons/4/47/Hydraulic_disc_brake_diagram.gif

If you cannot build pressure and keep it at any point, and have never used the system, chances are that the seals of the master cylinder piston have hardened or/and that the compensation and inlet ports are clogged.

JBinSD
March 28th, 2013, 08:04 AM
Than guys, helpful thoughts. IGeeker, I did remove the brake light switch with the new rear set install, so that could have affected it. I did elevate the caliper and put a wrench between the pads too, and it would hold a seal upon elevation, but lose pressure only after the caliper was bolted on the perch. Replacing the line with SS today, hope that's the fix, but I appreciate the input guys, thanx :-)

JBinSD
July 18th, 2013, 04:21 PM
Just reviving this thread again, as I still haven't gotten the rear brake working. I noticed there are some curious bracket type things on the right side of the swingarm, and now I'm wondering if that affects the caliper and how it sits on the perch.
checking to see if anyone's messed with this and figured it out before. . . .
Thanx,
joel

felo
July 18th, 2013, 04:26 PM
Just reviving this thread again, as I still haven't gotten the rear brake working. I noticed there are some curious bracket type things on the right side of the swingarm, and now I'm wondering if that affects the caliper and how it sits on the perch.
checking to see if anyone's messed with this and figured it out before. . . .
Thanx,
joel
that bracket type things is where the oem brake hose goes
http://www.wallgc.com/images/2012/12/2011-kawasaki-ninja-250r-petal-shaped-disk-brake-image-gallery-a.jpg

JBinSD
July 18th, 2013, 04:35 PM
Thanx Felo, I knew it was for the brake hose, but that pic helps by pointing out the pistons on my caliper seem to be hitting the hose brackets, that may be a reason why the brake is not functioning. I also noticed I routed my brakeline differently, so it approaches the banjo from the front, instead of looping around to the back. Not sure if that has an impact or not. .. hmm.

JBinSD
July 18th, 2013, 04:50 PM
I'm also wondering if I have the caliper perch flipped or something; after looking at the picture of the 250 caliper and mine, it looks like my caliper isn't far enough forward.

Anyone have a pic of their (working) 300 caliper? Doubt they're diff than the 250, but ya never know. . .

felo
July 18th, 2013, 04:54 PM
I'm also wondering if I have the caliper perch flipped or something; after looking at the picture of the 250 caliper and mine, it looks like my caliper isn't far enough forward.

Anyone have a pic of their (working) 300 caliper? Doubt they're diff than the 250, but ya never know. . .
i have a 300 and is the same , the only difference is that the 300 caliper is black
http://www.motostarz.com/media/catalog/product/cache/1/image/9df78eab33525d08d6e5fb8d27136e95/c/d/cde6684ac8d29f8625c53888bc1b428b_3.jpeg

JBinSD
July 18th, 2013, 04:55 PM
i have a 300 and is the same , the only difference is that the 300 caliper is black

OK, thanks, is the caliper forward of the hose guides, or right there? If you look at my pic above, my caliper actually contacts the hose clamps, and I think that may impede the travel of the pistons, does your caliper touch the hose guide?

felo
July 18th, 2013, 05:02 PM
well i dont have the bike close to tell you exactly but here are 2 google pics that i found
http://motoroids.com/wp-content/uploads/2013/05/Kawasaki-Ninja-300-review-India-7-399x600.jpg
http://www.motostarz.com/media/catalog/product/cache/1/image/9df78eab33525d08d6e5fb8d27136e95/c/d/cde6684ac8d29f8625c53888bc1b428b_3.jpeg

just try and take the line out and do the process again, try and get the caliper out and push the pistons in , if that makes any diference. just take your time

alex.s
July 18th, 2013, 05:14 PM
regardless of the outside of the caliper or what its pressed against, putting hydraulic pressure into the cylinder should expand the piston out into whatever. doesn't matter if its doing it correctly or not. and it should put resistance on the pedal at a certain point. if you do not reach a point where enough pressure is built up to extend the piston, and not enough pressure is built up to hold the pedal back, then you have a leak in the system somewhere. could be seals, maybe the line. if the brake caliper pot cylinder was rusted and not moving you would still build pressure in the master and the pedal would have resistance. the fact that the pedal never gets enough pressure to provide resistance means that pressure is either not being built up or it is quickly dissipating. my vote is on a damaged master cylinder seals.

JBinSD
July 18th, 2013, 05:23 PM
hmm, thanx Alex, but the thing is only 6 mos. old, and I replaced the line with SS, AND it pressures up when the caliper is not on the perch, so I'm trippin' as to why it loses pressure once its put in place. . . I guess its possible the master cylinder seals were fried from the beginning, as I've never used a back brake before, but since I seem to enjoy a good runoff at Chuck rather frequently, I guess I need to get it dialed. . .

Xtina
August 2nd, 2013, 06:44 PM
So if there is not pressure on the pad and you keep putting fluid in the reservoir, where is the brake fluid going? Is it leaking out? If there's fluid in there it has to go somewhere, either leak out or compress the caliper.

Lychee
August 2nd, 2013, 07:59 PM
So if there is not pressure on the pad and you keep putting fluid in the reservoir, where is the brake fluid going? Is it leaking out? If there's fluid in there it has to go somewhere, either leak out or compress the caliper.

here is a really insightful question.

JBinSD
August 4th, 2013, 06:21 PM
The volume of fluid is not increasing, but the pressure is dissipating somewhere.

sousuke86
August 6th, 2013, 02:26 PM
When you bleed the caliper make sure you have the bleeder screw facing UP.

You'll get pressure but air bubbles will remain in the line no matter how much you bleed them.

csmith12
August 6th, 2013, 03:20 PM
I just had this happen to me today. Mine was a crimped in the large feed tube from the fluid reservoir to the master cylinder. When the raised rearsets are installed, it kinks the stock feed tube. NO crimps or kinks in the main. :p

JBinSD
August 6th, 2013, 03:26 PM
Hmm, thanx guys, I'll check them both and see if there's any air. . .

csmith12
August 6th, 2013, 03:35 PM
What mine looked like for reference.

http://i41.tinypic.com/oqj7n8.jpg