76 280 C Brake booster check valve...saga continues...

[Tomas7]

The car misses at idle and the brake light is on. Yesterday night the light was off and the car idled fine when I drove to the store a few minutes away.
This leads me to believe that there's a vacuum leak related to the brakes???????
The check valve is new (it could be faulty or the wrong one).
Could there be an issue with the brake booster itself, If so how do I check?

Thank you all very much in advance and have a great 2018!

[CTD]

Could the check valve have been installed backward? How do the brakes feel? When operated without a check valve, the power brakes would cut out immediately if the engine stalled.

[fonzi]

If you have a moment mighty-vac, see if the brake booster holds a vacuum. Remove the vacuum line and shove a cone shaped mighty-vac attachment into the space and get a workout on your hand.


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[Tomas7]

Originally Posted by CTD

Could the check valve have been installed backward? How do the brakes feel? When operated without a check valve, the power brakes would cut out immediately if the engine stalled.

Black side to the manifold and white side to the brake booster, right?

[Mike D]

If the check valve were reversed you would have no power assist to the booster. I'm pretty sure you would have noticed this by now.

[Tomas7]

Originally Posted by CTD

Could the check valve have been installed backward? How do the brakes feel? When operated without a check valve, the power brakes would cut out immediately if the engine stalled.

The brakes feel fine.