MG Car Repair: 74 mg midget brake bleeding, disk brakes, father inlaw

Question
Hello I have a 74 midget that I am restoring for my father inlaw. I am all but done but can not get this thing off the jacks until I get this brake issue solved. I have all new brake parts all the way around except for the lines which have been blown out and the master cylinder. I have tried every method of bleeding the brake with no luck, I still have a soft pedal. My car guy friends have even strayed with no luck. I know I do not have a leak in any of my lines and have tried standard bleeding by pumping the brakes and have used a vacuum hand pump. I have also followed the bleeding procedures in the chiltons book. I do not think the master cylinder is bad because I do build up some pressure at some point in the process. I would love some in sight before I spend another 180.00 on a new master cylinder, which is my next step. This car is a gift a I am WAY over my budget. Thanks for any advice you can offer. Rob

Answer
Hi Rob,
When you replace everything and have a soft pedal. You need to try this, Remove the new front pads and temporarily install the old thinner pads. Just slid them in place, you don't need to lock them in with the pins. Then pump up the brakes as much as they will pump up. Then slide the old pads out and pry the piston in just enough to force the new pad in one at a time. If you pry the piston in too far and the new pad slides in freely you need to repeat the process over. The objective is to have the new pads in by forcing them in and a hard drag on the disk. When you have done that on both sides check the pedal. If it is now good, drive the car at a slow speed in hard "S" turns and then jack the front up and spin the wheels to see if they have freed up a little.
The only retraction device these disk brakes have to relieve the pressure on the pads to disk is the counter flexing of the seals and what happens often on new seals or new calipers is that the seals over flex and retract the pistons too much so what I gave you is a method to put the seals in a more neutral position.
Another method to isolate a brake problem is to get a set of assortment of brake bleeders and remove one line from the master cylinder and put a bleeder in it's place so only one circuit is used at a time to find which is causing the problem, the front or the rear.
Howard