hard brake pedal is the most obvious sign only way i know to test a booster, is to turn engine off. use brakes several times till pedal is hard. then with brake applied,start engine. the brake pedal should then soften.if the pedal stays hard the booster is bad
you will have a hard brake pedal
bad o2 sensor Could also be a power brake booster going bad.
BAD power brake booster are a vaccum leak at the booster.
Your power brake booster is probably bad.
The power brake booster is bad.
Sounds like the power brake booster is bad.
Sounds like the power brake booster is bad.
You may have a bad power brake vacuum operated booster.
The brakes will be real hard to push.
The power brake booster may be going bad.
Start the engine and then push the brake pedal down. If it is soft and easy to push then the booster is okay. If booster is BAD the brake pedal would be hard to push.
A bad brake booster will cause a vacuum leak, result in poor braking, and even poor engine performance. The brake booster has a large diaphragm which can fail and leak.