My C5 Tourer – No brake pressure on cold start

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Dremark
Posts: 1
Joined: 07 Mar 2026, 17:05

My C5 Tourer – No brake pressure on cold start

Unread post by Dremark »

Over the past few days I have experienced that my **C5 Tourer 2.0 from 2014** does not have pressure in the brake system when it has been parked overnight, for example.

When I press the brake pedal, the pressure builds up and then the brakes work normally again.

It is not losing any brake fluid.

Has anyone here experienced this problem?
– And do you know what might be wrong?
– And possibly whether it is something I can fix myself (I normally service all the mechanical parts on our cars myself)?
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xantia_v6
Forum Admin Team
Posts: 10910
Joined: 09 Nov 2005, 22:03
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Re: My C5 Tourer – No brake pressure on cold start

Unread post by xantia_v6 »

The brakes get their power from a vacuum pump mounted on the end of the cylinder head. There is a vacuum reservoir built into the brake booster. It sounds like you have a leak in the vacuum system, maybe in a hose or non-return valve.