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Old 11-25-2010, 08:30 AM   #1
Casey Stangle
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Default How to bleed a front brake

I rebuilt the front disc on my CX500. Calliper kit as well as the Master Cylinder. I can not get the front brake to pump up firm. I was told that there is an air lock in the system. I tried opening the bleeder and applying the brake and then closing the bleeder and letting the hand grip return to normal. Did thid a lot! I do not see air bubbles comming through the clear tube that I put on the bleeder. Any thoughts?
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Old 11-25-2010, 11:11 AM   #2
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No pressure at all? The proper sequence is to apply the brake lever, then open/close the bleeder before the lever reaches the grip. Opening the bleeder first will let air into the system before the lever is squeezed.

The next thing is the banjo fitting at the master cylinder. It is like a hollow barrel, and the bolt that holds it has a hole drilled to let the fluid pass. This can often be bled by making the fitting lower than the master cylinder, and cycling the lever. Pull the lever slowly, hold a second, then release it quickly; repeat. This will usually pull the air back into the master cylinder and out. Last resort is to loosen the bolt, keeping the fitting snug enough not to leak, then use the same procedure you use with the bleeder: apply pressure, loosen then tighten the bolt before the lever reaches the grip. Messy, so make sure the fluid can't spill on anything painted or polished, it will stain and strip paint.
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Old 11-25-2010, 11:12 PM   #3
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Quote:
Originally Posted by Casey Stangle View Post
I rebuilt the front disc on my CX500. Calliper kit as well as the Master Cylinder. I can not get the front brake to pump up firm. I was told that there is an air lock in the system. I tried opening the bleeder and applying the brake and then closing the bleeder and letting the hand grip return to normal. Did thid a lot! I do not see air bubbles comming through the clear tube that I put on the bleeder. Any thoughts?
Keep doing it. Make sure to keep topping off the fluid level in the reservoir.

1) Open the blled valve at the caliper

2) apply slow lever pressure

3) snap the bleed valve closed BEFORE the end of the lever stroke.

4) release lever

Repeat as many times as needed.
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Old 11-26-2010, 07:31 AM   #4
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When I rebuilt my GL500 brakes I was surprised at how long it took to get the air out. Just keep working at it.
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Old 11-26-2010, 02:50 PM   #5
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I tried the gravity method. Several riders suggedted it to me. I let three master cylinders of fluid drain through. It still will not come up. I also tried the open and close of the bleeder. That also did not work. I may try to get a vacuum bleeder and try that. If that fails, I will have to take the MC appart again.
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Old 11-29-2010, 08:14 PM   #6
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Took the MC appart and found that the piston from the rebuild kit was shorter than the original. I either ordered the wrong one or was sent the wrong one. I put the old one back in, after cleaning it up and putting a little silicone grease on the seal, and everything worked. I do not like the K&L ones because they have no on line list of kits by bike. George Fix does not even tell you what kit you are getting. The Honda kits are twice as expensive, but at least you know what you are getting.
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Old 11-30-2010, 08:56 AM   #7
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Wow, that bites! Sure explains why you couldn't get any pressure, though.
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Old 11-30-2010, 09:19 AM   #8
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Viva la Diffeance'!
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