Stiff brake pedal

[alexsv_17]

Hi, I have a stiff brake pedal after the car has been sitting for a while. I noticed the problem a month ago. At the beginning it has been doing it after sitting for at least 12h, it began stiffening after a couple of hours recently. After starting the engine, the pedal depresses slowly as usual and there are no problems.

There is no hissing sound when depressing the brake pedal, from that I conclude the brake booster is OK. 

From my experience with my previous petrol cars I know there must be a vacuum check valve before the brake booster. It might be visible or integrated into the pipe. 

Could you point me the vacuum check valve on the diagram on my vehicle, I cannot find it? 

Also, could the Egr valve be the culprit of vacuum loss?

P. S. The car is a Corolla 2.0 D4d 1cd-ftv engine with the vacuum egr

[oldcodger]

Hi,

According the the Haynes manual this is the check valve, in the servo body,  and they say it can be removed "in a pulling and twisting " method.

They say its tested by simply blowing though it and it should only alow air though one way, if not renew, also check the grommets and rubber pipe for leaks.

Was a bit surprised at your comment about it lasting 12 hours as, after swtich off,  ours has always gone hard to push down after the first press and release, but the brakes still work , just that you need that extra force.