Dual circuit brake failure

[TvrJohn]

Hi
recently the brake pedal has dropped and only works from half way
not spongy pedal

was thinking that maybe a brake pipe had burst

jacked the vehicle up and i can rotate either rear wheels when the brake pedal is fully pressed with the engine running !

looked all around the rear hydraulics, and there are no visible signs of brake fluid anywhere ?

checked the resevoir and front and rear sections are full of fluid as normal

What do you think

master cylinder seal failure on rear set ?

[steveo3002]

was it jacked in such a way that the wheels hung down , alot of cars have a valve so that in that position there would be little braking and fully loaded would be lots of braking

otherwise its a case of taking things apart to see if they still move