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Reverse Bleeding?


betaben
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fed up of trying to bleed my brakes on my rev3, no other bike i have ever bled the brake on has ever been such a pain.

so i am considering giving reverse bleeding a try with the syringe does anyone know if this works better or does this damage the seals?

Thanks Ben

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are you trying to bleed front or rear ?

front is easy, turn the bars to full left lock so M cyl is as high as possible

back off adjuster screw on the lever so there is lots of free play and zip tie the hose so that there is no part of the hose higher than the connection with the master cylinder.

then push the pistons back in the caliper forcing fluid and any air back up the pipe to the master cylinder, don not touch the bleed nipple. Air rises in fluid once you get it moving so any air will end up in the Master cylinder and bubble out of the top.

pump the lever a few times and that should be it.

If that doesnt work usually there is a seal gone somwhere or a leak in the hose or joint.

to do the rear brake principles are the same but its harder to get the flow right, on a beta rev 3 you can remove the system without taking it apart and bleed it on your bench.

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Hi Ben,

Don't let the cheeky little monkeys freak you out (brakes not other members). They should bleed just fine. I use a long (1.5m) piece of clear tube for my brakes and clutch bleeding. One end on the nipple the other end clipped up high at the handle bar.

Bleed as normal but the benefit will be noticed using a long clear tube. You can see whats in there, how far if at all etc it is pumping through and you get no air locks anywhere as the air can shoot up the tube. try this first.

Back bleeding works well if you have too but my trusty clear tube method has never failed me yet - even when I fitted a new dry clutch master cylinder to my Rev 3 the other day.

Edited by pindie
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When in doubt as a last resort, burp the banjo bolts, you will often find air there

And I agree with baldilocks on pushing the piston back into the caliper, just watch that you don't over flow the master and make a mess and once you have the pistons pushed back in put a clamp on the caliper and bleed the system if it still feels mushy

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Biggest problem is normally trying to bleed with the pistons not seated as far they will go...if they are on their way out you will have real problems getting the air out....strange but true I have a Corvette Stingray with a pair of 4 pot calipers and have learned this the hard way!

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The answer to your question is yes, and no, you won't damage the seals because you are putting much less pressure on them than when you use the brake and, as you may be fearing, you are not putting pressure on them "in the wrong direction" - pressure is equal throughout a fluid, which is the principle on which a hydraulic system works, so it's essentially the same as operating them but with the lower pressure mentioned.

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HI

im still haveing problems bleeding the brakes, there is a little bit of pressure at the lever and the brakes are working fine at the calpier.

The caliper was recently cleaned out at college and new pads were fitted. So the only fault i can assume is the there is something wrong inside the front mastercylinder?

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HI

im still haveing problems bleeding the brakes, there is a little bit of pressure at the lever and the brakes are working fine at the calpier.

The caliper was recently cleaned out at college and new pads were fitted. So the only fault i can assume is the there is something wrong inside the front mastercylinder?

Make sure there is a bit of free play at the plunger where it contacts the master cylinder piston. The MC piston must be able to return all the way to the stop in order to uncover the small return hole or it can trap pressure and air in the bore. Sometimes if you look closely you will notice that when the MC plunger returns all the way out to the stop a small air bubble will come out of the return hole and float up in the reservoir. This is how it should be and flicking the lever to cause these small bubbles to back out of the bore is often the easiest way to get that last bit of air out. Having the steering turned to full lock so the MC is tilted to allow the air to return is also helpful. I have never had to use a hose or syringe to bleed any brake or clutch system on any bike nor have I had to reverse bleed any of them. (I'm either lucky or damn good) :irish:

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I'm with lankydoug. I never seem to have issues when bleeding brakes or clutch but I always make sure everything is backed off when doing it so it can let air out at the top and at the nipple when opened.

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