Have a 79 Scout II, 304, auto. I replaced the wheel cylinders recently and had new calipers put on the front by a local shop and had them bleed the system. Now my pedal gets soft every once in awhile. It will get soft and I'll really have to get on it to slow down, but then it will come back and be good for awhile. Do you guys think I just need to bleed again or is it time for a master cylinder?