Rear Brake Bleeding Trouble

dwright0723 · May 7th, 2014, 04:34 PM

Howdy! I'm having some issues with my rear brake! I bleed it, and it stays firm for a little bit, then slowly looses pressure again to where I have to push the rear brake lever all the way down for it to work. I bleed it again, and it works for a bit and the pedal again gets lower and lower. It's done this several times. I'm not losing any fluid at all. Any ideas as to what going on here?

sonny4472 · May 7th, 2014, 05:01 PM

Still has air in the line.

C-Bass · May 7th, 2014, 06:04 PM

I have just developed the exact same problem on my bike!

I did the bleed thing, but haven't fixed it. More thought required....

sonny4472 · May 7th, 2014, 06:11 PM

Did either of you replace your lines? Sometimes it takes more than you would think to completely bleed a system.
I prefer to use a sealed bleeder tube full of brake fluid. Sometimes you can still pull more air into the system while you are bleeding.
If you aren't leaking any fluid than you can assume it's something else.
As time goes on, using the brake system will actually compress the air and push it to the pistons. This feels like the brakes are getting squishier with use.
I hope I explained that ok...

mgentz · May 7th, 2014, 06:12 PM

Junk in the threads or air in the line. Pull the blender out all the way and clean both the caliper and the bleeder.

dwright0723 · May 7th, 2014, 06:16 PM

Quote:

Originally Posted by sonny4472

Did either of you replace your lines? Sometimes it takes more than you would think to completely bleed a system.
I prefer to use a sealed bleeder tube full of brake fluid. Sometimes you can still pull more air into the system while you are bleeding.
If you aren't leaking any fluid than you can assume it's something else.
As time goes on, using the brake system will actually compress the air and push it to the pistons. This feels like the brakes are getting squishier with use.
I hope I explained that ok...

Nope, haven't replaced lines. I've been using a bleeder bottle with fluid in it as well.. pump it up, open the bleeder, repeat till no more bubbles... Starting to get into a habit of not using the rear brakes..

dwright0723 · May 7th, 2014, 06:18 PM

Quote:

Originally Posted by mgentz

Junk in the threads or air in the line. Pull the blender out all the way and clean both the caliper and the bleeder.

Alright, I'll have to try this..

sonny4472 · May 7th, 2014, 06:23 PM

Hmm, I'm now wondering about mileage. The brake line could be overly soft and relieving pressure.
BTW, Sport bikes have rear brakes?!

dwright0723 · May 7th, 2014, 06:26 PM

Quote:

Originally Posted by sonny4472

Hmm, I'm now wondering about mileage. The brake line could be overly soft and relieving pressure.
BTW, Sport bikes have rear brakes?!

I have like 3k miles.. lol you don't use your rears?

C-Bass · May 7th, 2014, 06:28 PM

My bike is new, only 500 miles on it. And no loss of brake fluid.....wtf??

sonny4472 · May 7th, 2014, 06:36 PM

I bet you two have two different issues.
This is what I would do:
Drain the entire system, check the brake line, stainless is always nice if it needs to be replaced.
Pull the caliper, pull pistons clean and lube everything (including bleeder and passageway)
Re assemble and refill, re bleed.
It's a super simple system, shouldn't be difficult to fix.

No, I use my rear brake, but only in emergency stops, gravel and maybe really wet weather. It's just a matter of preference for me.
* I replaced my rear pads on a bike at 30k miles just cause I felt like it.

EDIT
Check to make sure your fittings are all tight. Also your reservoir cap, just to make sure no air is being pulled in.

C-Bass · May 7th, 2014, 06:48 PM

Air has gotten into the system on mine somehow - checking all the fittings for tightness is a good suggestion - thanks!

dwright0723 · May 7th, 2014, 06:57 PM

Quote:

Originally Posted by sonny4472

I bet you two have two different issues.
This is what I would do:
Drain the entire system, check the brake line, stainless is always nice if it needs to be replaced.
Pull the caliper, pull pistons clean and lube everything (including bleeder and passageway)
Re assemble and refill, re bleed.
It's a super simple system, shouldn't be difficult to fix.

No, I use my rear brake, but only in emergency stops, gravel and maybe really wet weather. It's just a matter of preference for me.
* I replaced my rear pads on a bike at 30k miles just cause I felt like it.

EDIT
Check to make sure your fittings are all tight. Also your reservoir cap, just to make sure no air is being pulled in.

Yeah, it looks like a super simple system. Thats why I'm so stuck lol.. Ill take it apart tomorrow and lube..

Lol at 30k miles?! wow! I don't feel as bad not using them now

sonny4472 · May 7th, 2014, 07:02 PM

It's a matter of preference that could probably start a whole posting war, but I'm not new enough or advanced enough to really have a use for the rear brake.
Oh, to clarify something I worded stupidly earlier; don't lube the bleeder or passages, I just kinda stuck all that in one sentence. Just lube the pistons.

EDIT
https://www.ninjette.org/forums/showthread.php?t=147436
This DIY covers a lot of good angles.

dwright0723 · May 7th, 2014, 07:26 PM

Got ya! Thanks for the link!

May 7th, 2014, 04:34 PM	#1
dwright0723 ninjette.org member Name: Darryl Location: OSU/Dayton, OH Join Date: May 2013 Motorcycle(s): 08 Ninja 250 Posts: 121	Rear Brake Bleeding Trouble Howdy! I'm having some issues with my rear brake! I bleed it, and it stays firm for a little bit, then slowly looses pressure again to where I have to push the rear brake lever all the way down for it to work. I bleed it again, and it works for a bit and the pedal again gets lower and lower. It's done this several times. I'm not losing any fluid at all. Any ideas as to what going on here?

May 7th, 2014, 06:36 PM	#11
sonny4472 ninjette.org member Name: Sonny Location: Saint louis Join Date: Apr 2014 Motorcycle(s): 09 250r, 09 1125r, 95 Virago Posts: 78	I bet you two have two different issues. This is what I would do: Drain the entire system, check the brake line, stainless is always nice if it needs to be replaced. Pull the caliper, pull pistons clean and lube everything (including bleeder and passageway) Re assemble and refill, re bleed. It's a super simple system, shouldn't be difficult to fix. No, I use my rear brake, but only in emergency stops, gravel and maybe really wet weather. It's just a matter of preference for me. * I replaced my rear pads on a bike at 30k miles just cause I felt like it. EDIT Check to make sure your fittings are all tight. Also your reservoir cap, just to make sure no air is being pulled in. Last futzed with by sonny4472; May 7th, 2014 at 06:39 PM. Reason: I think slow.

May 7th, 2014, 07:02 PM	#14
sonny4472 ninjette.org member Name: Sonny Location: Saint louis Join Date: Apr 2014 Motorcycle(s): 09 250r, 09 1125r, 95 Virago Posts: 78	It's a matter of preference that could probably start a whole posting war, but I'm not new enough or advanced enough to really have a use for the rear brake. Oh, to clarify something I worded stupidly earlier; don't lube the bleeder or passages, I just kinda stuck all that in one sentence. Just lube the pistons. EDIT https://www.ninjette.org/forums/showthread.php?t=147436 This DIY covers a lot of good angles. Last futzed with by sonny4472; May 7th, 2014 at 07:08 PM. Reason: Lorazepam makes me slow

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May 7th, 2014, 05:01 PM	#2
sonny4472 ninjette.org member Name: Sonny Location: Saint louis Join Date: Apr 2014 Motorcycle(s): 09 250r, 09 1125r, 95 Virago Posts: 78	Still has air in the line.

May 7th, 2014, 06:04 PM	#3
C-Bass ninjette.org member Name: C-Bass Location: Alberta Join Date: Mar 2014 Motorcycle(s): Currently own: 98 Honda VTR1000, 02 Suzuki's DR200 & DR650, 04 & 08 BUSA's, 05 Ducati SS1000, 12 Ninja 250R SE Posts: 59	I have just developed the exact same problem on my bike! I did the bleed thing, but haven't fixed it. More thought required....

May 7th, 2014, 06:11 PM	#4
sonny4472 ninjette.org member Name: Sonny Location: Saint louis Join Date: Apr 2014 Motorcycle(s): 09 250r, 09 1125r, 95 Virago Posts: 78	Did either of you replace your lines? Sometimes it takes more than you would think to completely bleed a system. I prefer to use a sealed bleeder tube full of brake fluid. Sometimes you can still pull more air into the system while you are bleeding. If you aren't leaking any fluid than you can assume it's something else. As time goes on, using the brake system will actually compress the air and push it to the pistons. This feels like the brakes are getting squishier with use. I hope I explained that ok...

May 7th, 2014, 06:12 PM	#5
mgentz Board Member Name: ... Location: WI Join Date: Dec 2011 Motorcycle(s): 250R (street), 250R (dirt) Posts: A lot.	Junk in the threads or air in the line. Pull the blender out all the way and clean both the caliper and the bleeder.

May 7th, 2014, 06:23 PM	#8
sonny4472 ninjette.org member Name: Sonny Location: Saint louis Join Date: Apr 2014 Motorcycle(s): 09 250r, 09 1125r, 95 Virago Posts: 78	Hmm, I'm now wondering about mileage. The brake line could be overly soft and relieving pressure. BTW, Sport bikes have rear brakes?!

May 7th, 2014, 06:28 PM	#10
C-Bass ninjette.org member Name: C-Bass Location: Alberta Join Date: Mar 2014 Motorcycle(s): Currently own: 98 Honda VTR1000, 02 Suzuki's DR200 & DR650, 04 & 08 BUSA's, 05 Ducati SS1000, 12 Ninja 250R SE Posts: 59	My bike is new, only 500 miles on it. And no loss of brake fluid.....wtf??

May 7th, 2014, 06:48 PM	#12
C-Bass ninjette.org member Name: C-Bass Location: Alberta Join Date: Mar 2014 Motorcycle(s): Currently own: 98 Honda VTR1000, 02 Suzuki's DR200 & DR650, 04 & 08 BUSA's, 05 Ducati SS1000, 12 Ninja 250R SE Posts: 59	Air has gotten into the system on mine somehow - checking all the fittings for tightness is a good suggestion - thanks!

May 7th, 2014, 07:26 PM	#15
dwright0723 ninjette.org member Name: Darryl Location: OSU/Dayton, OH Join Date: May 2013 Motorcycle(s): 08 Ninja 250 Posts: 121	Got ya! Thanks for the link!