Chrysler Repair: Braker Booster 99 Dodge Grandcaravan, vacuum gauge, diagnostic protocol

Question
99 Dodge GrandCaravan, 3.8L, 163,00 miles.  
The brake booster was replaced.  After about 2" of brake pedal movement I have to push hard on the pedal to stop. I hear a "hiss" noice (like air escaping) under the dash when the pedal is depressed. When I'm stopped, I have about a 2" pedal play and can hear the "hiss" when I depress the pedal.  I can move the brake pedal back and forth those 2" and the brakes still stay engaged.  Not at all like a master cylinder leak and there is no gradual stop when the pedal is depressed.

A week after the booster was replaced I had a puddle of brake fluid on the garage floor. The reservoir had been overfilled and another shop removed the overfill.  The source of the leak was never located but the mechanic suspected that it came from where the fill tube connects to the reservoir and was overfull. No fluid leaks yet so I suspect that part is taken care of.

Is it a bad booster? Hoses not connected?  What suggestions do you have that I can take to the repair shop.  I've had it to them twice and their answer is "you'll get used to the new feel". I liked the "old feel" better.  

Answer
Hi Robert,
Earlier this month I answered your question about your car and hope that is is repaired now. I have a favor to ask:
I am competing to be recognized as 'volunteer of the month' at this site. Would take a moment to click on the "Thank/rate the expert" button below?  You will then see a question which asks whether to nominate me for that award. If you then click on "yes" that would give me another vote. Thank you for your help.
Roland






Hi Robert,
The booster system diagnosis relies upon the use of a vacuum gauge. There is a diagnostic protocol* to sort out the the possibilities which are that the booster is defective, a vacuum check valve may be leaking, vacuum hose or fittings may be defective or loose, or vacuum seal on the master cylinder may be defective. Without the gauge it is not possible to sort out which. This is something that the shop which installed the booster should correct to return the function to normal. You could do the followint: Open the hood and with the aid of a helper to press on pedal, listen for the hissing sound while he applies the brake, with the engine idling. That may identify the location of a leaking fitting.
The work needs to be reviewed by the supervisor to find the cause and correct it, ideally with no further charge.
Roland
*I can xerox that and postal mail it to you.
PS Please rate my answer.