Nissan Repair: rpm drop when braking, nissan almera, simple test

Question
Nissan Almera 98, when I brake, at the stop there is a drop of the RPM to 400-500 and then recovers to 750.
I was told by my mechanic that the booster should be repaired?

Answer
Hello -

Sounds like it. Please do this simple test. Pull out the vaccuum hose that goes into the booster, and plug the engine side. Depress your brake pedal and if there is no engine RPM drop, replace the booster. Another test is to run the car for about a minute or two, turn it off, and wait 20 seconds. Press the brake. If it is hard to press, your booster is not working.

Hope this helps -
aloha
calvin