Brake problem

[b3coupe]

Hi all, my b3 20v coupe failed mot today on poor rear brakes:aargh4: mot man thinks it may be a problem with the rear brake load sensor, having removed it today can anyone confirm if the 2 small pressure points which the lever presses on should move freely? as i can't push them in with my thumb or have they seized.
can anyone explain what happens inside the block to control the flow balance between front and rear brake load or recommend futher reading
cheers steve

[b3coupe]

UPDATE Brake problem

mot passed, rear brake problem caused by elongated worn nylon bush in the brake spring and weak spring, replaced complete spring assembly, no more brake probs