Help!

I'm in the process of rebuilding my MK and decided to bleed the brakes today. I used a speed bleeder (the one that uses air pressure to pump fluid through. And everything seemed to go ok, but when I press the pedal it just went flat to the floor! No amount of pumping(ooh err) could coax any sort of life out of it. I reverted to the two man method to bleed the brakes to see if the pedal was actually doing anything and it's definitely pumping fluid round the system (how much I don't know though) everything worked fine when I took it apart....

I'm running a sierra master cylinder with wildwood power lives up front and sierra calipers at the back. Everything was brand new 3 years ago but the only thing I can think of is the seals are shot in the master cylinder?


Does anyone have an idea on this?

Thanks

Sounds like a seal somewhere in the system (or a bleed nipple has been left open and you've missed the puddle )

Could it be a fluid compatibility problem? DOT5 doesn't like to be mixed with anything else (DOT4 or DOT5.1) getting that wrong destroys the seals.
Stripping down the master cylinder would tell you for sure and doesn't take any time on the one's I've done (though never done a sierra master - didn't know you could get non-servo sierra's) just remove the circlip/snapring and pull out the guts.

Are the bleed nipples for the rear caliper at the top? If not then you need to unbolt the caliper and turn it so the bleed nipples are the top to bleed it, then bolt it back back on when bled.

If none of the above then use a bleed nipple to blank off ports on the MC to test / diagnose which circuit the problem is with.

Cheers
Davie

Thanks guys I'll try the bleed nipple trick first.. what a waste of dot 5.1