ive changed pads, discs, calipers, hoses and master cylinder and still have problem can you help

 

Does it have ABS? Could it be a problem with the control unit?
I assume you are dragging a front brake so it's not a problem with a corroded parking brake cable.
With all the things you have mentioned, the only other things involved in the braking action are the pedal and the caliper brackets. Inspect the brackets carefully to make sure they're not notched or worn and are properly lubricated. They don't do much other than sit there and resist movement.
Make sure the pedal is free to move and doesn't have a left foot riding on it. (It happens.)

 

I have found it to be a little module which is fitted to the inner wing next to the fuse box under the bonnet were there is a small breather pipe coming off the servo to it then another pipe from that to the back of the engine I have taken the pipe off the module yellow in colour and it seems to be fine but now need to find the relay or fuse to the module the yellow pipe is just sucking air in now can you help