Brakes Firm Until Servo Comes On

[Lan 24 1 Cars]

Hi there i'm having some trouble with the brakes on my car, new m/c lines etc... bled nicely

 

nice firm pedal, until I start the engine and the servo comes into play I then have a pedal with lots of travel which is significantly softer

 

I've periodically checked all the lines and bled the brakes and I still have this issue the brakes feel spot on without the engine running and then crap thereafter

 

any help appreciated

 

thanks

 

Lan

[rallyeash 155]

what calipers and master cylinder you using?

 

obviously the pedal drops down with the engine running as the pedal gets "pumped" up when the servo isnt getting any vaccum. (ie engine off)

[Cameron 16]

Sounds normal to me!

 

Unless it's really spongey or going to the floor, servo'd brakes are normally a lot softer when the engine is running.

[Lan 24 1 Cars]

normal 19mm mc, good condition bendix front calpers, yeah i do expect that from servo'd brakes but i wasn't expecting this much travel its not all the way to the floor but its not far away either, ill check it over again when i'm home from work

[rallyeash 155]

normally will go down a couple of inch's