Author Topic: '77 CB400F front brake -- bleed technique suggestions, please...  (Read 1505 times)

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Offline mwc400f

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'77 CB400F front brake -- bleed technique suggestions, please...
« on: September 13, 2021, 07:41:58 PM »
The master cylinder and the front brake caliper were leaking, and the front brake was dragging pretty good, so I replaced the front caliper assembly with a new one, and rebuilt the master cylinder with a genuine Honda rebuild kit. Motion Pro Master Cylinder snap ring pliers and *plenty* of patience were required to disassemble/clean/reassemble with new parts.

I bled the brakes as per the shop manual instructions. The good news is that the brake no longer drags at all and the brake lever is nice and smooth, plus there are *no* leaks. The bad news is despite bleeding the brake until the bubbles disappeared,  I have to pump the lever 1.5-2 times to get full braking power. Any suggestions for solving this problem?  I plan on trying and bleeding the brake again in a day or so -- hopefully whatever bubbles are there will have migrated to a location where they'll come out.

Thanks in advance.

Offline mwc400f

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Re: '77 CB400F front brake -- bleed technique suggestions, please...
« Reply #1 on: September 29, 2021, 07:25:29 PM »
Turns out the M/C needed bleeding -- and I happened to stumble on a method to bleed the M/C on the bike -- if you gently pump the lever by about 1-1.5cm *only*, bubbles start issuing from the "pin hole" port in the M/C. Continue doing this until the bubbles stop. You're done.