Hello,
I just had my master cylinder replaced (Crossfire 2005 limited) under warranty and I have been paying close attention to my brakes and have 2 questions.

A. If you start the car, keep you foot on the brake, release the parking brakes, move car to D back to P while you have your foot on the pedal, turn off the car, Pedal stiffs up and moves back up by an inch. Is this normal?

B. On the brake booster, while the engine is running and car in park, I can hear a hissing noise, it comes from the vacuum connector on top of the booster. When first dealer changed my master cylinder, they knocked that connecter semi lose, and caused my CHK ENG light to come on in 3 miles of driving, when I took it back and complained to their service manager and had him check the light and listen for this odd noise, he pullout the vacuum line from the booster and noise went completely away, he had plugged the vacuum line with his finger, then he placed it back on the booster and had his tech check the ERROR code and they said that was due to line getting knocked lose while they were working on the car, they reset everything and I have not seen the CHK ENG lite for the past 20 miles, but I still hear the noise if lift the hood and go near the booster, the problem is I never noticed it before, and again, I was not listing for it either. Does that connector supposed to have a natural leak?

 

A, Yes.
B, No

 

OK, thank you. So for part B. If that is really a problem will I get any sort of "chk eng" light or any indicator comes on? How can it be tested?

I think the techs at my local dealer ship are not so good, even for the master cylinder issue, I had to reproduce it for them, they had missed it completely, the next dealer is 40 miles away.

Please advise.

 

You need to locate the leak if it exists, is it at the valve that pushes into the boost unit body or is it a leak in the body itself. Use a hose to your ear, moving the other end of the hose around the unit. It is quite possible that there is no leak and you are hearing a normal sound.

The one way valve is pushed into a seal that uses vacuum to prevent leaks, it could be damaged. I would have thought that the hiss would be obvious in the seconds after switching the engine off as air entered the boost body until the pressures had equalized. All seals leak so an extended period of parking would see the vacuum lost, I have no idea how long that would be though.

 

OK, I will try those tests, I also have a stethoscope, I will try that as well.

Thank you.

 

UPDATE.

The issue with my Brakes were with Master Cylinder (there were no fluid leaks), the follow up issue was that the tech at Mall of Georgia Chrysler dealer at North of Atlanta, had forgotten to install the bushing (gasket / seal) between the master cilynder and power booster causing the brakes to malfunction and result in a vacuum leak between Master Cylinder / Booster which subsequently caused engine light to come-on. I have logged a compliant with Chrysler Customer Service and have written the dealer as well.

To fix the leak issue, I took the car to EdVoyles Chrysler and they found the Master Cylinder gasket to be missing and once they replaced all is working fine, my brakes are firm and tight.

My research on this topic showed that, it is real important that you use the Original equipment parts and specially brake fluid from Chrysler. This car being German build and most / all part being German the brakes should be firm and should not fade or slip.

PS, on a side note, while my car was at EdVolyes, it had a rear windows detachment, which was also fixed by replacing the whole convertible top at no charge, it looks like Chrysler warranties the top for 100K miles (real good thing done by Chrysler).