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post #7 of (permalink) Old 25th July 2012
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Re: brake pedal, slowely, descends, to floor renault scenic

OK, after a bit of research, I found this:

202: Brake pedal creeps ***8211; Vehicles with diesel engines.
Diesel engine vehicles usually use a pump to generate the vacuum for servo assistance. Unlike the inlet manifold of a petrol engine, there is no vacuum relief with a pump. If excessive pedal pressure is applied when the vehicle is stationary (and the engine is running) the hydraulic pressures required to stop the vehicle will be grossly exceeded and fluid will be forced past seals that are between circuits. Larger vehicles such as vans and 4x4s are more prone to this problem as they use servos with a higher boost ratio. The phenomenon is known as diesel creep; and it is often incorrectly diagnosed as being caused by a faulty master cylinder. The solution is to stop applying the excessive pressure.

Important! If you can get the brake pedal to creep with the engine switched off and servo exhausted, or actually under braking there is a serious problem that requires urgent attention!

So it seems, that this phenomenon is not necessarily a problem.

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