[thunder_taz]

Don't know if I am asking a stupid question, But I recently swapped my front brake and clutch master cylinders on my Thunderace for XJR1300 items. The clutch was fine, but after several hours if trying I could not get the front brakes bled. The wierd thing is that level of fluid in the master cylinder didn't seem to be going down much. I couldn't see any signs of any fluid leakage, and when I removed the brake lines from the master cylinder and pulled the lever. the fluid would start to come out, but then it would get sucked back in again with hardly any coming out.

Does this mean I need to get a rebuild kit for he master cylinder?

 

[shinyribs]

Sounds like its cavitating. Like the MC itself is not bled.

If you hold your finger over the hole for the brake bolt (directly at the MC) will it make pressure? If yes you probably don't need a kit.

Motorcycle brakes are inherently difficult to bleed. The MC moves such a small amount of fluid and air doesn't like to float down hill like your need it to.

When I bleed motorcycle brakes I use a pump type oil can with a hose connected to the bleeder at the caliper and pump the fluid backwards through the system. Once it fills the reservoir you're done. All fluid, no air, go ride.

Good luck.

 

[Guest]

It sounds like the lever is not allowing the piston to come fully out (fairly normal) take the lever off & push the piston carefully with a screwdriver, make sure you let it out fully between pumps do this a few times bleeding at the caliper as normal & the fluid should begin to move then you can put the lever back on & continue as normal

Just make sure you dont slip with the screwdriver & split the dust seal