Hard Brake Pedal

[avensisTR1415]

Noticed this maybe 3 time in the last six months... last time i went out to move my car in the car park 2 mins engine running all fine.... come back to the car 40 - 60 mins later.... with engine not started brake pedal is hard as a rock not possible to press it in at all... start the engine returns to normal right away.... is this normal???

[acetip]

Sounds like the servo. If its fine with the engine running then turn engine off then pump the brake pedal untill the pedal goes hard.

Does the pedal now feel like as you describe. If so, its when the car is stopped the reserved brake assistence as drained off.

Not sure how long this reserve should remain in the servo when engines not running.

If you keep your foot on the brake pedal when its hard and engine not running then start the engine if you feel the pedal move down a little then its ok and all working ok. youve nothing to worry about.

[igormus]

check with vacuum actuator + an impulse tube connected with suction manifold -- whether or not the tube has clear hole?

the worse case -- a force membrane might to be cracked communicating both sides of the same membrane.

regards / Igor