a couple of things. 1: does it drive good doesnt stumble when driving if not the carby might be flooding..... 2: if it runs great and only dies when the brakes are applied, does it idle rough then die, it might be the brake booster.
maybe your tcc solenoid, which is in the transmission. my 84 montecarlo did that with a new carb
The power brake booster is bad.
A leak in the brake booster is one common reason why a car would stall or hesitate when the brakes are pushed. There could also be an obstruction in the brake line.
the brakes were not fixed properly some part is installed wrong
Yes, but the entire braking system would need changed. It would be easier and cheaper to buy a car with ABS.
I would check the point gap and timing first. If that does not correct it, I would check the carburetor float level.
It can be the idle control solonoid on the throtle body.
you might have a vacuum leak in your intake manifold
speedo hooked up or working properly? Assuming that has the 2.8 L engine with a carburetor, the carburetor may be in need of a rebuild.
It could be a leaking vacuum hose to the power brake booster or the membrane in the booster could have a hole. When the brakes are applied, the booster is opened to the engine vacuum via the hose. The vacuum leak would then increase, causing the engine to stall.
You can get brakes from any automotive supply store or the dealership. I would highly recommend that you have them professionally installed, since if they are installed incorrectly you could get into a car accident. Brakes can be done at almost any type of repair shop, however I would usually go to one that is recommended for that particular service or the dealership.
There could be a fouled out spark plug that would cause this. However the carburetor is the most common issue with these symptoms.
Fuel starvation. Blocked air/fuel filters. Fuel pump delivery rate wrong or carburetor needle valve stuck.