My 76 Ford Courier has developed a massive rain leak behind the glove box. I suspect the air vent in the fire wall has plugged or come apart. Any quick fix suggestions?
My guess is you have a blocked drain. There is a drain for the water that comes into the car through the vents in front of the windscreen. The drain is usually located under the car just in front of where the passenger puts their feet.
Clean out any old leaves etc. that may have collected in there and then use a low pressure air source or some string trimmer line to clear that drain. Don’t overdo it or you may disconnect or damage the drain line.