Pressure sounds at start up

[JB 3.2]

In my bid to cure an intermitent problem with the ABD light, I notice that when I first start the car I can hear a pump trying to pressurise at the front of the car (to the RHS of the front compatrment lock, when viewed from the front). It appears to achieve the required pressure once the car is started.

I can also hear what I presume is the same pump briefly adding pressure when I apply the brakes after not using them for a few mileas.

Are these pressurising sounds normal?

 

[Mark Elder]

Yes, mine does exactly this.

If I switch on ignition after leaving car over night it always runs for quite a while (maybe 30 seconds, although I've not timed it, perhaps more). When I restart car during day it's only a few seconds.

When driving I can't hear it (it's too quiet), but in traffic or when I'm pulling slowly into my drive I sometimes hear it at other times.

At morning start up the "brake pressure" warning light seems to come on sometimes while the the pressure is building. I did not notice this before car was serviced in summer and fluid changed. It's as if the new fluid is thiner and more difficult for the pump to obtain the right pressure. Anyway, light is always off by the time I've reversed out of my awkward drive, so I think it's OK.

 

[ach]

The brake pressure warning light indeed come on after switching the engine and stays on for some 10 seconds. In 4S manual it is specifically mentioned as normal (it is really because the pressure is building up). I am not sure about Carrera 4, but would assume it should be the same...

 

[fergusond]

another one that agrees with the above hydraulic circuit booster pump typical cycle, check the condition of your ABS sensors and plug in connections on each wheel hub, its some where to start.

David