Hi any help with my brakes i have ap racing 4 pots 330mm. So when i brake they feel sharp how they should but if i let off and put back on i get litrally nothing a stiff pedal why is this 

I fitted new reardisks (256mm) not long back could this cause the issue? Should i have to bleed the fronts. Ive checked the lines that go to tandem pump not splits or anything

Check the non return valve on the servo vacuum line, I'm guessing it's sticking.

3 minutes ago, sepulchrave said:

Check the non return valve on the servo vacuum line, I'm guessing it's sticking.

Thanks ill check