brake bleeding nightmare

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scheckaet
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brake bleeding nightmare

Post by scheckaet »

Is there a special trick to bleed the front KX lines?
I'm having trouble with it, had no problem with the rear or the front KDX.
I have the motion pro speed bleeder and they worked well with the other lines I've done.
I cleaned everything in the master cylinder, changed o rings in the calipers and cleaned the line with compressed air to removed the junk that was in it.
I tried
-normal flush/fill from the top with the speed bleeder (usually works great)
-reverse flush/fill from the bottom with a syringe
-fill the caliper and line from the bottom with syringe without the master to make sure I had no air in the line and caliper. Then re-install the master, fill it up, pump to get the air out, still not working
I even hung the caliper above the master overnight to let the bubble go up.
Still nothing, nada.

I'm out of idea.
Any tips? tricks

Thanks

Wilf
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WNC
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Post by WNC »

Did you try hanging the master cylinder above, leaving the cap and rubber seal off? (take the master off the bars). Leave the caliper bleed nut tight also. If not try that. Make sure the line is straight. Fill the tank, and pump the lever LIGHTLY about every 10min or so. You will see bubbles escaping and begin to feel the lever tighten after a bit.

I have had the same problem and this trick worked for me.
It might take an hour or so.
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Indawoods
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Post by Indawoods »

Push it up through the line from the bleeder with a piece of tube and a big catheter syringe from a medical supply place. That's how I do it and have never had a problem. Takes about 10 minutes.... :wink:
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RBD
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Post by RBD »

Kind of sounds like a master cylinder problem....

Disconnect and remove the brake line at the master cylinder. Fill the reservoir with brake fluid and then put your index finger over the brake line hole in the master cylinder.

Pump the lever a few times and hold the lever pulled all the way onto the bars and then release your finger keeping the lever pulled in. Then put your finger back over the port hole again and hold it there. Now release the lever and pump the lever again, keeping your finder over the port. Now hold it to the bars and release your finger..... You are using your finger as a check valve.

You keep doing this until the master cylinder will push your finger off allowing brake fluid to spurt out.

If you can not make the above work, you still have a problem with the master cylinder like a bad or nicked seal or clogged reservoir port. Make sure the very small ports that go from the reservoir to the cylinder it self are open and free of debris. When doing the above test, when pumping the lever you should see small swells coming up into the reservoir.

Some times it is really hard to bleed the air out of the master cylinder (the above will help diagnose where the problem is in the system), so if you can get it to squirt with the finger test the rest of the system should bleed just fine.

Ron
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scheckaet
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Post by scheckaet »

I tried both already and nada, the brake doesn't firm up I don't see any more bubbles coming up but I can pull the lever all the way to the bar, with 1 finger so something's up.
I'll have to try again the reverse flush a 3rd time :roll:
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scheckaet
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Post by scheckaet »

thanks Ron, I'll try that.
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