Leaving work this morning, I did not have any power boost for my brakes. First thought was that the vacuum line had come loose, but seems to me that the car would be running like crap if that were the case. Pulled under a light in the lot anyway and looked, but the hose was still connected. The brakes worked, but needed extra effort, just like when engine isn't running. Drove home carefully, being mindful of needing extra time to slow. (Fortunately it was 2:30AM and very little traffic and few lights between work and home.) Then, about 2/3 of the way home, about 25 min. of driving, the boost came back.

Any thoughts on what to check?

 

Possible check valve problem. The check valve is supposed to prevent air from leaking back into the booster when the engine is off. Usual symptom is no boost on start-up, but it comes back soon thereafter. Your problem seems a little different, but it's a cheap and easy replacement.

 

Thank you, dcotter. I will "check" that out.

 

Looked in my Haynes manual, and it doesn't have any instructions on replacing the check valve. From looking at the part on Auto Zone and the booster itself, it looks like it just presses into the front of the booster. Is that how it goes?

 

That's all it took to replace the one on my Mercury Mariner. I can't imagine Chrysler would do it much differently. This ain't rocket science.

 

Thanks.