Brakes dont start till pedal is half wau down. Not spongu.

[hotrodjohn71]

Thank you. I changed out the master cylinder today to fix a long time problem of the brake pedal going down about half way before activating the brakes. Not spongy but good action after half way. I bench bled the master, bled the 4 wheel cylinders in the correct order and I don't know if it was correct but I cracked open each of the lines to the ABS/TCS unit while a partner pushed the pedal for pressure and there was no air at all. The new master cylinder made no difference at all. I had my front rotors turned a while back. Do you think that could be the cause?

 

[hotrodjohn71]

Sorry, meant to say not spongy.

 

[EmmJay]

Some ABS systems need to be bled via software commands. Conventional bleeding methods won't remove the air from the ABS block that modulates the line pressures in many systems. I suggest checking into this. I know this is the case on my 2010 V8 Mountaineer. My guess is the Mustangs probably have the same ABS system.

 

[Mustang5L5]

You'll need to cycle the ABS pump. If there is any air trapped inside, it will not be released using conventional means. This can be done at home via ForScan (www.forscan.org)

Anecdotally, i've heard that finding a gravel road and locking up the brakes to cycle the ABS will achieve the same function. never done it this way and confirmed that it does work however.