1978 Mark Blowing White Smoke

Hey Bill,
You answered a previous question for me and I was hoping you could help me out again. I have a 78 Lincoln Continental Mark V (the diamond jubilee edition) with the 7.5L 460, and I am having an issue where the car is blowing white smoke. I know that most people would assume head gasket, but when I checked the oil everything looked fine. Also, its very odd because when I start the car up I can leave it running in park for a very long time and there is no smoke present. I step on the accelerator while in park and no smoke either. When I put the car into drive and start driving there is no smoke, but once I step on the brakes and the car comes to a stop, pillows of white smoke are emitted from under the car around the front wheel on the driver side. The car is garage kept and there is nothing leaking on the concrete. When I looked underneath I did notice that there is an exhaust leak around the catalytic converter and/or the flange exhaust pipe and I was wondering could this be the cause. I keep hearing that white smoke is a sign of coolant, but someone else said that since there is a leak that there can be condensation in the pipe and once the car is driving that its causing it to steam and blow out from the leak. Any help would be very much appreciated. Thanks again.
Jimmy
—————————————————————————————————————-
Hello Jimmy –
From your description and symptoms it is clear to me that someone would need to be there with the vehicle to find out exactly where the white smoke is originating from. We cannot determine from here if it is actualy billowing from the left front wheel and brakes or from under the car somewhere. We would need to road test your car and then drive it to a safe area when it smokes to open the hood in order to pinpoint the problem. A good mechanic should have no problem finding the exact cause with no guessing.
Sincerely,
Bill