Brake problems. Still!

[cahurst2001]

I having an issue with the front disc brakes on my CB360. Simply put: I can't get the brake fluid flowing. The brakes were completely disassembled. Nothing remained connected and all the pieces got a good cleaning. I also purchased a supposedly functioning BMC and lever from an 82 Magna V45, including the banjo bolt, to replace my old, broken one.

I marked all the holes of the banjo bolts and the brake lines to make sure they lined up. Opened up the speed bleeder on the caliper, filled the BMC w/fluid, pumped quite a few times and got nothing. Little resistance and no fluid out of the bleeder.

I did lower the front end, so the lines are a bit curvy, but not in a way that should impair gravity from moving things along.

Am I not waiting long enough? Not pumping enough? Recheck my lines? Elevate the BMC to get it flowing?
Any suggestions, fellas?

Thanks!

 

[ridesolo]

Re: Brake problems

Sounds like your master cylinder needs a re-build. If everything is connected and you pumpity-pumpity-pump and nothing comes out it sure sounds to me like the MC isn't pumping. If there were some kind of blockage there ought to be some resistance on the handle when you pump. Put a piece of hose onto the bleeder valve, run the bottom of the hose into a jar w/ a couple of inches of new brake fluid in it, open the valve and pump. You should get bubbles out of the hose until all the air is out.

 

[cbcafe]

Re: Brake problems

Before you rebuild the master cylinder, see if you can find a vacuum bleeder to pull fluid through your brakes via the bleeder screw on the caliper. Master cylinders can be a bitch to get going when they are completley drained. I had the same problem with both my Maxim and my cb and that vacuum source had my brakes functional in seconds.

 

[cahurst2001]

Re: Brake problems

Before you rebuild the master cylinder, see if you can find a vacuum bleeder to pull fluid through your brakes via the bleeder screw on the caliper. Master cylinders can be a bitch to get going when they are completley drained. I had the same problem with both my Maxim and my cb and that vacuum source had my brakes functional in seconds.

where's the best place to get a vacuum bleeder? just a cheap one at the auto parts store?

will this work? http://www.youtube.com/watch?v=kgpY_oGINU8

i would think the vacuum wouldn't be powerful enough, but the idea is the same.

 

[cbcafe]

Re: Brake problems

That setup should work. What I use is very much the same except that the vacuum source is a venturi unit driven by compressed air.

If you can get a buddy to help, have them keep the reservoir full of brake fluid while you control the bleeding operation. Don't stop drawing fluid until it runs clear. Tighten the bleeder screw and test the brakes. With any luck you will have a solid brakes. If not ,it is time to order a mc kit.

 

[cahurst2001]

Re: Brake problems

Well, no luck on fluid. I disassembled the MC, checked the parts, and reassembled to see if that would help, but no dice. Rebuild kit is in the mail.

 

[cahurst2001]

Re: Brake problems

Ok, hate to resurrect this thread, but I'm still having issues. This is the last thing keeping my bike off the road and it's getting damn frustrating.

Got the MC kit in the mail and rebuilt MC. Hooked it up and pumped. Still nothing. I decided to start over b/c there must have been something I missed. I disassembled the entire front brake system except caliper. I did have a clog in one of the lines, but I blew that out and reattached all lines. Checked the lines by blowing air and there were no clogs. Air flowed freely.

Reattached MC, lined up banjo bolt w/the upper line, tightened the line, and pumped. Nothing. Pumped again. And again. Still nothing. I tried using the banjo off my old MC thinking by some slim chance it would work, but it didn't fit right.

When I have the MC off the bike and the banjo bolt in and pump, it pumps fluid out of the holes in the banjo bolt easily. I haven't tried hooking up my vacuum setup to try and pull it through b/c it's 1a.m. and my neighbors wouldn't be too pleased.

Sooooo...before I try that tomorrow after work, do you guys have any more thoughts?

 

[matt365]

is there a nasty kink in the lines or anything? I'd take the caliper off and let it hang while you do this. air won't really like to take too many corners in my opinion. Other than that, when I did my CB, I used nothing other than a 8mm wrench, a piece of tubing, and an empty bottle... and my lines were conpletely dry.

add fluid, pump the brakes to add pressure, and then relieve the pressure by cracking the bleeder open, then turning it closed. I had to pump the hell out of it though...