Intermittent hard brake pedal (new vacuum pump)

[94250turbo]

I put a new vac pump on my truck and im still having problems. The brake light also comes on too. The other day I had to brake really hard and my brake pedal literally got stuck. I played with it for a sec and it came back up. Is this the booster?

 

[franklin2]

Got stuck? Do you have a hard brake pedal like in your title or the pedal is getting stuck down?

 

[pickupman]

Usually if you have a bad booster you will hear a hissing noise that is very noticeable when you apply the brakes, at least that has been my experience when they fail.

According to the factory service manual that I have, the way to check for a bad booster is to T a vacuum gauge into the line coming off the vacuum pump. Apply and hold the brake pedal. If the vacuum falls below 21 inches HG, it indicates a problem with the booster.

I should also mention that it is a good idea to firstly rule out the new vacuum pump as being bad, because if it isn't producing enough vacuum to begin with, then that test would result in a false positive.

 

[94250turbo]

Got stuck? Do you have a hard brake pedal like in your title or the pedal is getting stuck down?

It intermittently gets real hard. The time it got stuck I was applying the brakes really fast/hard.

 

[franklin2]

Are you pumping them? When the engine is idling, the vacuum pump is not turning very fast and after a couple of pumps you can run low on vacuum.

 

[ZWilson07]

EDIT: saved for later.