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Mushy front brakes -- need advise

Started by Odeccut, June 01, 2008, 07:55:07 PM

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Odeccut

June 01, 2008, 07:55:07 PM
Hi guys!  I need help:  my front brake goes soft on me every once in a while.  Most of the time it is fine, but every once in a while I can pull it almost all the way to the grip.  The brake engages and stops the bike well, but I am just worried as to why every once in a while the travel of the lever changes so much.  In addition, I am keeping the lever adjusted kind of far from the grip, because if I adjusted it closer, I am afraid it will run into the grip one of those times and I will not be able to stop the bike.   Any ideas?  I tried bleeding the brakes a few times, but I am kind of new to it... Please help -- I am getting really nervous about this.

ducpainter

#1
June 01, 2008, 08:06:23 PM
Air in the line is possible, but it usually doesn't come and go.

A bad master is a possibility too.
"Once you accept that a child on the autistic spectrum experiences the world in
 a completely different way than you, you will be open to understand how that
 perspective
    is even more amazing than yours."
    To realize the value of nine  months:
    Ask a mother who gave birth to a stillborn.
"Don't piss off old people The older we get, the less 'Life in Prison' is a deterrent."


mdriver

#2
June 01, 2008, 08:47:00 PM
Don't take chances like that. :o   If its not leaking, and bleeding it doesn't help right away, change the master cylinder.
Bike Info: 2001 Ducati M750 Dark, 2007 Triumph Bonneville

Speeddog

#3
June 01, 2008, 08:48:08 PM
Which master cylinder do you have, Goldline or Coffin?

How old is your bike?
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He Man

#4
June 01, 2008, 11:00:08 PM
 check for loose bolts, then rebleed. then see if it fixes the issue. if not, check for leaks

Odeccut

#5
June 02, 2008, 07:27:52 AM
Quote from: Speeddog on June 01, 2008, 08:48:08 PM
Which master cylinder do you have, Goldline or Coffin?

How old is your bike?

The bike is an '02 620.  It has coffins.  The problem started when I loosened the banjo bolts to get my handlebars fitted -- I needed to move the brake lines around.  While messing with it, I had the reservoir open and like an idiot pulled the brake lever -- don't ask why :).  The brake fluid shot up into the air... Anyway, I put it together, bled the brakes, but ever since then it goes mushy every once in a while.

teddy037.2

#6
June 02, 2008, 07:42:46 AM
Quote from: Odeccut on June 02, 2008, 07:27:52 AM
The bike is an '02 620.  It has coffins.  The problem started when I loosened the banjo bolts to get my handlebars fitted -- I needed to move the brake lines around.  While messing with it, I had the reservoir open and like an idiot pulled the brake lever -- don't ask why :).  The brake fluid shot up into the air... Anyway, I put it together, bled the brakes, but ever since then it goes mushy every once in a while.

sounds like you just have air somewhere. have you bled the MC by itself?

mighty vac also helps. makes bleeding stuff a snap  [thumbsup]

Desmostro

#7
June 05, 2008, 09:43:18 AM
Quote from: teddy037.2 on June 02, 2008, 07:42:46 AM
sounds like you just have air somewhere. have you bled the MC by itself?

mighty vac also helps. makes bleeding stuff a snap  [thumbsup]

How do you do that?  Details of the best way please?
If you're not living on the edge, you're taking up too much room

Slide Panda

#8
June 05, 2008, 10:20:04 AM
Quote from: Desmostro on June 05, 2008, 09:43:18 AM
How do you do that?  Details of the best way please?

Some, but not all, Masters have bleeders on them.  So you bleed at the calipers to replace the fuild and get ride of old gunk.  Then you can also bleed at the top, since air rises in the fluid and bleeding from the bottom may take longer/may not get it all.

If you don't have a bleeder on your master, you've jsut got to do it from the calipers the old fashioned way.
-Throttle's on the right, so are the brakes.  Good luck.
- '00 M900S with all the farkles
- '08 KTM 690 StupidMoto
- '07 Triumph 675 Track bike.

ducpainter

#9
June 05, 2008, 10:43:22 AM
Coffins have no bleeder on the master.

You can bleed it by having some one squeeze the lever and holding a rag at the banjo and just crack the fitting while it's being held with pressure on the lever.

Works great except for needing an extra hand.
"Once you accept that a child on the autistic spectrum experiences the world in
 a completely different way than you, you will be open to understand how that
 perspective
    is even more amazing than yours."
    To realize the value of nine  months:
    Ask a mother who gave birth to a stillborn.
"Don't piss off old people The older we get, the less 'Life in Prison' is a deterrent."


teddy037.2

#10
June 05, 2008, 02:08:24 PM
Quote from: ducpainter on June 05, 2008, 10:43:22 AM
Coffins have no bleeder on the master.

You can bleed it by having some one squeeze the lever and holding a rag at the banjo and just crack the fitting while it's being held with pressure on the lever.

Works great except for needing an extra hand.

+1

and not making a mess of yourself and the fluid  ;) bled my goldline clutch master that way, since only the brake master had a seperate bleeder.

Howie

#11
June 05, 2008, 07:37:39 PM
The master should be as close to level as possible.  Wire tying the lever in the applied position over night can help too.
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