Problem with the brake m/c on the 1200.

[John Schmidt]

I rebuilt both the clutch and brake, clutch works fine and I adapted the wiring on the controls to the GL1200 and that works fine. I first used a K&L kit, same as used on the rear brake and the clutch, both work fine. I couldn't get any brake action on the front m/c with it so picked up a Honda kit and installed it today. Only difference is the return spring is about 1/4" shorter on the Honda part, but after going through nearly another quart of fluid, still no brake. When the line is removed from the m/c and I put my finger on the opening, I don't get any pressure when squeezing the lever. Shouldn't there be some pressure there, been so long I don't recall from working on others. I checked the small passage and it's open, blew through it with slight air pressure. At the moment, I'm stumped and looking for suggestions. I keep getting air in the bleeding but there are no loose connections, any tighter and they'll strip threads. I'm tempted to just buy a new m/c and be done with it but at this point I'm not sure it's the m/c itself.

[Andy Cote]

You probably already know this but brake lever goes to left side caliper on the GL1200.  Pedal has metering valve and links rear and right caliper.

[John Schmidt]

You're right Andy, but I did away with that split braking. Never liked it so isolated the rear to operate just the rear caliper with the pedal and capped off the second output that originally went to the front. I now have the front m/c operating both front calipers, same as the Valk. All lines are new SS, the front has one line going to a tee mounted on the bottom tree, then splits off left and right from there. The handlebars, controls, and both m/c are from a Valkyrie and I adapted the controls to the 1200 wire harness. This afternoon I ordered a new front brake m/c from ProCaliber, $86.67 with priority shipping, should be here next week. I have bled the system to the point of no air bubbles, but still have nothing from the m/c.....even with a new Honda kit installed. It's so weak I can't even use Speed Bleeders, really bugging me.

[Blackduck]

Guess you blew through the small hole while it was apart.
With the top of the cylinder are there any air bubbles coming out of either of the holes or sign of fluid moving back into  the reservoir?
Sounds like the piston is not coming back far enough to recharge the cylinder with fluid.
Is there clearance between the lever and piston when in normal position?

[mark81]

i had a similar issue with my old cb750c. after replacing the master and lines to fix it, I finally noticed the caliper slides were sticking and not letting the caliper self center over the rotor.