I have an 80 as well and most of them from 77 up have power brakes. This should be a dual system with aproportioning valve. Meaning two or three lines from the master. Two will go to the fornt and one to the rear. If you dont' have that system it has been supposedly "fixed" to work that way. That may be your problem unless one of the discs in front are stuck, which could mean that you have the wrong master and it is set up for a drum brake instead. It would keep pressure on the front brakes which would give you the problem youare experiencing. Try this one www. Universitymotorsltd. Com and go to tech section. Type in brakes. If all else fails you can call there at 1p.M every day as the guy there is a world renowned MG specialist. He may offer some suggestions as well, but things don't sound kosher to me from your description.
Monday, February 6th, 2012 AT 4:54 PM