[72k5]

You can get a quick idea about your booster by simply disconnecting the booster and plugging the hose to the manifold. If the engine now idles well, the booster is leaking. You can often hear the booster hissing if it is leaking enough to cause the engine to die.

Another easy way to get an idea if the booster is leaking is to run the engine, driving the vehicle or simulating it by snapping the throttle shut from about 3,000 rpm a couple of times. Shut off the engine and wait 10 minutes. Apply the brake without starting the engine. If you still have power boost for the first couple of brake applications, the booster is not leaking. If you get no boost at all, either the booster is leaking or you have very serious vacuum problems with your engine.

I'm betting the booster is OK and you have other problems with your motor, esp. since you say it wants to die. More likely you have a vacuum leak at the intake, carburetion, or timing issues. Investigate these thoroughly, and get your engine running well before you replace the booster. Many things on these old trucks can cause the brakes to be less than impressive, and it would be a shame to waste good coin on something you don't need.

I don't know if the newer booster will work.

Good luck with it.