Hello friends. Just wondering if anyone would know the cause for my brake problem on my 1960 Cadillac. I was told by some that the brake booster is bad although there is a vacuum valve installed between the carb and the booster that might have an issue. I think that the valve is ok although it is old but the thing is when the car is cold and I start out driving the brakes work fine. After the car warms up some and I have driven it some the brake pedal gets harder and harder to push down. I can't seem to find even the valve to replace it and the brake booster will cost well over $200.00 to send off and get rebuilt. I would do this if this was definitely the problem but don't want to waste the money if thereare other possible causes for this to happen. Any help would be very much appreciated.