brake pedal sinking c5 hdi

sportingfiat · Unread post by **sportingfiat** » 05 May 2010, 18:33

after changing my faulty caliper and bleeding the system twice, if you start the engine and press the press they go hard but if you keep your foot on the pedal it slowly over 10-15 secs sinks to near the floor

is there something else to bleed as well as the brakes or any ideas whats up?

does sound like a pump running somewhere near the master cylinder too, is this the abs pump?

cheers

h2ocooler · Unread post by **h2ocooler** » 05 May 2010, 20:03

My guess is the master cylinder seals are letting by, if the pedal goes hard then sinks its not air in the system, it would still be soft.
ABS pump would not kick in unless you were moving.
Rob

Unread post by **RichardW** » 05 May 2010, 20:27

Some modern cars just seem to do this - you may simply not have noticed before as you have never tried it whilst thinking about it. I'm pretty sure the Vectra (yeah, I know!) does it for instance. Any other C5 drivers confirm the status of their sinking??

dnsey · Unread post by **dnsey** » 06 May 2010, 05:40

Yep, my C5 does the same. The brakes work well, have been bled, and I can find no (external) leaks.
I think it's just one of those things.
I can't imagine ever having to brake hard and long enough for the pedal to run out of travel!

Citroenmad · Unread post by **Citroenmad** » 06 May 2010, 08:51

sportingfiat wrote: does sound like a pump running somewhere near the master cylinder too, is this the abs pump?

cheers

Is the pump a sounds a of small running motor over towards the n/s strut top? I have that one mine, though i only hear it when ive turned the car off and got out. Its quiet but easily heard in the garage. Seems to stay running for a few minutes after stopping the car. Anyone know what that is?

Unread post by **myglaren** » 06 May 2010, 17:14

Could be the motors closing the ventilation flaps.

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brake pedal sinking c5 hdi

brake pedal sinking c5 hdi

Re: brake pedal sinking c5 hdi