Thread: Soft brakes - Replaced master cylinder, ABS block, bled with Hawkeye and still soft!

Originally Posted by discorevy

As you've worked out that you have a hard pedal with blanks fitted at the banjo ends, and have tested the master cyl , then you've obviously worked out the problem is air in one of the callipers if there is no leaks.

Try introducing one calliper at a time into the system, seeing you have the ability to isolate

pretty sure there's no air. It's weird though -
only 2 fronts connected = all good
only 2 rears connected = all good
2 fronts + 1 rear connected = soft sinking pedal (either rear)


going to try diagonals next, as that is how the abs modulator circuits work

Originally Posted by Robflocar

A buckled or loose disc will push the caliper piston in further on release of the pedal, then take a lot more fluid than normal to push the piston back out again when the pedal is pressed.Not talking a massive buckle because then the disc would pulse the caliper. Just a small amount. Not sure what the ABS and other braking smarts might do with this situation though.

A floating caliper will follow the warped disc, even when wheel bearings collapse, the pedal will pulse but it won't become long whereas a fixed piston caliper will suffer pad knock back from the tiniest bit of hub/bearing float (or vibration)