1969 RR 4 wheel drum brakes. New master and booster. I know I do not make enough vacuum to have a reliable booster. My issue is that everything is new. Drums cylinders shoes hardware hoses. Now when cold the car stops as it should. Has maybe a little extra pedal travel. Now once it gets hot when I barely touch the brakes the front right completly locks up. I was going about 10 mph in my drive way and checked this visually. I dont understand why my front right is locking up when hot. Please help as I want to drive it this summer and it is not safe right now.