78 280z poor braking

[kutukutu1]

i have 78 280z with 280zx rear disc conversion.

I would have thought the 280zx conversion would not have any issues with bias since it came from a 280.

My issue is that i can press the pedal about half way before i get any sort of braking happening. I can smash the pedal and the car will brake, but i cant lock all 4 tires.

All 4 corner calipers have been fully rebuilt, stainless braided lines so no deformation of hoses, new bleeder screws. Use vaccum bleeder on all 4 corners multiple times and at the master cylinder.

There are no leaks that i can see any where.

I did see online that the wilwood  master cylinder says it will solve braking bias with disc brake conversion. Is this my only solution? Is this applicable when using 280zx calipers?

Any help is appreciated.

[Zed Head]

Make sure that bleeder screws are at the top where the air bubbles are.  You can see the little channel for the screw.  The end of the channel has to be where the bubble lives.

[kutukutu1]

1 hour ago, Zed Head said:

Make sure that bleeder screws are at the top where the air bubbles are.  You can see the little channel for the screw.  The end of the channel has to be where the bubble lives.

Yes, all bleeder screws on all 4 calipers are at the top. Any other suggestions?

[Zed Head]

There are two chambers in the master cylinder, on the same piston.  Sounds like you might have blown one seal.  Since the pedal moves far it should be pushing a lot of fluid.  Somebody helped me solve a bleeder screw problem once when they noticed how much fluid was leaving and reentering the reservoirs.  Have somebody watch the reservoirs while you press the pedal.  If a lot of fluid moves there's air in the system.  If very little fluid moves you probably need a new MC.

You can have a bad seal inside but no fluid will leak out.

[kutukutu1]

Thank you Zed. Ill pull it and just rebuild it since it would already be out. Good measure on an old car anyway.