Front Brake Rebuild

If it's broken or just needs tweaked

Moderators: Volker_P, tidd650

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tario
Posts: 166
Joined: Sat Mar 07, 2015 2:26 pm

Re: Front Brake Rebuild

Postby tario » Wed Mar 22, 2017 1:20 pm

I just blast the circlip with wd40 and let it sit for a while. Then if you have a sharp nail or pointy prying tool you can work each end a bit looser by prying it out of it's groove. I also try to chip away as much rust as possible. My circlip pliers were not very helpful.(possibly because i have a really cheap set. After no less than 50 curse words it generally comes out.

My brakes would not flush out without a vacuum pump. Even with the pump it seemed like nothing was happening for a good 15min. This was after a complete disassembly and cleaning.

Make sure you keep the copper washers for the ends of the brake line. Or wait... you're supposed to replace them... I'm too cheap for that nonsense. What's the worst that could really happen if 90% of my braking fails though...
1979 cb650
1980 cb650

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Solomoriah
Posts: 50
Joined: Wed Jun 01, 2016 10:18 pm

Re: Front Brake Rebuild

Postby Solomoriah » Mon Mar 27, 2017 4:24 pm

I'm a believer in having a plan A and a plan B (at the minimum) so I ordered one of those generic replacement master cylinders. It's a 14mm unit, but given that my bike has a single disk I figured it would work. I still have the original master cylinder and the rebuild kit, and have not given up on putting it back on the bike... but I went ahead with plan B so the bike is ridable.

I primed the new master cylinder using your technique, Folsoml, and I have to say it worked brilliantly. Then I bled the brake until no more bubbles came out (bled it four times without bubbles before I decided all was well). Rode it around town a bit, making sure to take a route with many stop signs to test everything out, and it seems to work about as well as the original (crud-filled) unit.

So I'm good for now. I still plan to rebuild the OEM unit and put it back on, but maybe not for a while, now that I can ride it again.

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Folsoml
Posts: 1634
Joined: Sat Apr 07, 2012 9:02 pm
Location: North Florida

Re: Front Brake Rebuild

Postby Folsoml » Mon Mar 27, 2017 7:04 pm

Solomoriah wrote:I primed the new master cylinder using your technique, Folsoml, and I have to say it worked brilliantly.



Sweet! I'll actually do that with the entire system some times. Start with the MC, then add the first brake line and do it again, and so on until I get the caliper done.
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My Current Bikes: 2005 HD FLHTCUI Electra Glide Ultra Classic, 2007 Yamaha Vino,


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