Front brake Problems

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Nov 26, 2001
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#1
I am having problems with my front brake on my 1999 KX 250. I cannot get a solid feel at the lever, it feels mushy. I have changed the fluid and bled my brakes and it only gets to about 50% solid feeling. The brakes still work and I do not see any leaking fluid. I am thinking about re-building the master cylinder. Any suggestions would be greatful.
 

marcusgunby

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#2
Older KX brakes are like that-sometimes you can improve them but often not-try to back bleed the brake using a syringe and hose onto the bleed nipple.This pushes any air upwards into the master cylinder.
 

rickyd

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#3
Marcus,
Does this mean too shoot brake fluid up through the bleed nipple?? Reason i ask is i have this problem w/the kids kx65, front brakes are MUSHY!! Pads look fine, tried bleeding them the normal way w/no better results..
Thanks in advance,
Rick
 

Jaybird

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#4
That's what he means, ricky.

The same holds true for hydralic clutches. Coventional bleeding does not get it done. A syringe pushing the new fluid upwards/backwards is the best way to go.

I take a length of 6mm or 1/4" nylon tubing (any hardware or auto store) and
affix one end to the syringe (it will push on the tapered end of the syringe nicely if you have a large "cow medicince" type syringe--farm supply-3for a couple bucks...20 bucks for a KTM OEM syringe??? Not moi!)
The bike end I actually heat up the end of the tubing and while its almost melting hot, I affix it to the bleeder nipple. (place it as far as you can on the nipple)
It will cool and conform to the nipple real fast. Once it has, reattach (you should take off the syringe while doing the heating thing on the other end) the end to the syringe and start pushing new fluid up through the now open master reservoir. (Messy, have rags there)
I like to use the tubing to close the bleeder off as I'm still shooting fluid. The tubing now has a decent grip on the bleeder and makes it easy to twist the tubing while plunging to make sure it gets closed off with no residual air entering. Be sure to close the bleeder just a bit more with your wrench (or spanner for marcus' sake :) )
 

rickyd

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#5
You learn something new everyday, i will do this on his bike.. Thank You for the Info,
RIck :)
 

dirt bike dave

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#6
If bleeding on the bike fails, there is probably a stubborn bubble clinging to the inside of the hose.  Try removing the caliper, hose and master cylinder from the bike and hanging it straight on a wall for a few days.  Tap the hose every so often.  This will help the bubbles rise to the top.  Then bleed off the bike with the hose straight.  

I had to do this once on a KDX200 (Kawasakis seem prone to the mushy brake syndrome) and it made all the difference.  Sounds like a hassle, but after countless attempts at conventional bleeding, desperate measures can be required. 
 

viking20

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#7
You are sure the caliper move corrects on the sliding pins?
On road bikes you can often get a better feeling brake,by loosening the bleeder bolt and tape/strip the brake lever to the bars in fully open position overnight,it takes care of the air-bubbles itself this way...