UK Car Repair: SILVER SHADOW 2 BRAKES, shadow 2, rat trap

Question
I have a shadow 2 the front brakes seized on and caused me major problems i had the calipers replaced but the problem remained i was told to change the pipes to the front calipers and the rat trap pipes but it has still once again seized on when i brake fairly hard any suggestions on next course of action

Answer
As you know this is a rather complicated system. Which brakes froze on?  I doubt all front callipers did, I even doubt that two did -one on each side-! The problem would appear to be in a distribution valve, these are the two valves in the assembly covered by the rat trap- there are no hoses in there! It is quite common for a valve to stick in, under emergency braking, if this happens the brakes cannot release. There is nothing to rebuild in them, they just have to be stripped and cleaned.