Front brake bleeding

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Front brake bleeding

larry6ft
I have replaced the front master cylinder and rebuilt bought calipers. After all that , I have bleed the brakes over and over again.  I am lost for solution. the brakes are still soft. Is there something I am doing wrong. Any tricks to doing the brakes on this bike 1982 cb750custom.. Thanks
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Re: Front brake bleeding

TOOLS1
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The master cylinders on motorcycles do not move enough fluid to push the air down, and out of the calipers. The best way I have found to bleed motorcycle brakes, is to use a pump type oil can, and a piece of rubber vacuum hose. Connect one end of the hose to the oil can, and the other over the bleeder. Then use the oil can to pump the brake fluid up to the master cylinder. Also be sure to tap on the hoses as you bleed. This will dislodge any air bubbles trapped in the line.
TOOLS
Life is not about the number of breaths, you take, but the moments that take your breath away.
I don't have an anger problem. I have an idiot problem. Hank Hill
Never confuse education for intelligence.
Happiness is a belt fed weapon.
I just can't imagine what could go wrong.
No fire? No explosions? So whats the point of your story?
Those who are too smart to engage in politics are punished by being governed by those who are dumber. ~Plato
It couldn't be done, but the darn fool didn't know it, and did it anyway.
We all got problems. Ksharp
I like vintage bikes because they take me away from the clutter of technology that I work with everyday and back to a simpler time of mechanical elegance and simplicity.. "ninadm"
Darkwing Duck: The worst part of public transportation is the Public.
"That is awesome shit there" Re-Run
"Fear nothing, attack everything" Eric Berry
" Oh, you read that on the internet? Clearly it IS a massive problem. Of course it CAN’t be normal operation."

1976 CB 750-A X 2
1977 CB 750-A X 4
1977 CB 750-K
1976 CB 750 F
1981 CB 750
1966 Kawasaki SG 250
1981 KZ 750 LTD
1973 CB 350
1979 CM 185 Twinstar
1982 Honda XL 80
South of Eden (Kansas City MO)
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Re: Front brake bleeding

Re-run
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This post was updated on .
In reply to this post by larry6ft
Make sure you have no high spots in the lines. Think of a P trap under your sink, except upside down. This would trap air and nothing would get it all out.

There are some options. I just fill the master and pump while opening and closing the bleeder. I put pressure on the handle, crack the bleeder, pump and hold, then close bleeder and let go of the handle. It can be slow but it has worked very well for me. Even with a completely dry system. Just make sure the master never runs low or more air gets into the system.

Another option is the same method but to use speed bleeders. These install in place of the old bleed nipple. Crack them about 1/4 turn open and pump away.

Another option is a mityvac. This attaches to the bleeder and suck the fluid through. Very quick and easy.

After that, a large syringe can be used to push the fluid into the system through the bleed nipple. Also fast just needs a bit of work when connecting the hose to the nipple.

If you have trouble with air stuck, pump slowly. Fast pumping breaks big air bubbles into small bubbles that are very hard to get out.

NEVER let the master run dry, always keep fluid in it.

Once fluid is in, if there is a slight sponginess, use a rubber band or something and pull the lever back and tie it there. Leave it overnight with the cap on but not tightened down. This helps air to come up and surface but still keep crap out of the fluid.
The ride IS the adventure. The destination is just to get gas!
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Re: Front brake bleeding

larry6ft
In reply to this post by TOOLS1
When I do this do i leave the brake lever out or in?
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Re: Front brake bleeding

TOOLS1
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Just leave the lever alone. and let it hang where it wants to.
TOOLS
Life is not about the number of breaths, you take, but the moments that take your breath away.
I don't have an anger problem. I have an idiot problem. Hank Hill
Never confuse education for intelligence.
Happiness is a belt fed weapon.
I just can't imagine what could go wrong.
No fire? No explosions? So whats the point of your story?
Those who are too smart to engage in politics are punished by being governed by those who are dumber. ~Plato
It couldn't be done, but the darn fool didn't know it, and did it anyway.
We all got problems. Ksharp
I like vintage bikes because they take me away from the clutter of technology that I work with everyday and back to a simpler time of mechanical elegance and simplicity.. "ninadm"
Darkwing Duck: The worst part of public transportation is the Public.
"That is awesome shit there" Re-Run
"Fear nothing, attack everything" Eric Berry
" Oh, you read that on the internet? Clearly it IS a massive problem. Of course it CAN’t be normal operation."

1976 CB 750-A X 2
1977 CB 750-A X 4
1977 CB 750-K
1976 CB 750 F
1981 CB 750
1966 Kawasaki SG 250
1981 KZ 750 LTD
1973 CB 350
1979 CM 185 Twinstar
1982 Honda XL 80
South of Eden (Kansas City MO)