C3 brake pedal sinks to the floor; design error.

[Bodacious]

The Citroën of one of my family members has a problem with the brakes, does anyone recognise the issue and know how to solve it?
Sometimes whilst driving slowly, when the brake pedal is pushed, the pedal does not give resistance, allowing to push it a lot further, and not actually braking immediately. Obviously this feels very unsafe. The car has been to the peugeot/citroen specialised garage several times, but they cannot find the issue so far. The master brake cylinder has been replaced, the ABS pump has been overhauled, and checked again by the overhauling company, and it has been verified several times that no air is trapped in the braking system.

[RichardW]

Welcome along

This rang a bell, I'm sure I've seen it before - I found this on another site:

https://citroenc3owners.com/not-related ... t2851.html

Had mine in the garage and found the antiroll bar bushes had worn and the antiroll bar had moved towards the drivers side 4 inches , so when on lock the antiroll bar was pressing on the back of the osf calliper, pushing the piston back, had no knocking from the bushes, undid the antiroll bar bush clamps and moved the bar over so it was central, all sorted no more pedal loss on lock

[Sloppysod]

Weired i know, but it's worth a go, you have nothing to loose.
Push the brake pedal down as hard as you can, while down wedge a piece of wood between the pedal and the steering wheel, this will keep the system fully pressurise, then walk away for a loooong time, overnight (12+ hours) in the past has worked for me.

I know it sounds 'BS', but I have used this a few times over the last 40 years or so, to get rid of a spongy brake pedal after bleeding. I've not given much thought to the why, probably something to do with stretching the seals, anyway I know it worked for me.

Good luck.

[RichardW]

Funnily enough, the first 5 mins of this video explains it:

[Sloppysod]

Funnily enough, the first 5 mins of this video explains it

That is terrible, that is one hell of a design error and should really have been a recall, or failing that it should be added as a "Pay Attention" note, or what ever they call it, to the MOT.

[PaulC5]

Could this topic be pinned and titled a bit better so it is obvious it refers to the C3 brake pedal going all the way down due to poor design and wear in anti roll bar bushes ?

[Richard_C]

This is really helpful and putting C3 in the title would be good. I read it by chance, I like a "mystery" story

We have a 2017 C3, 60k miles bought 'nearly new' ex motability 500 miles so we know it well. Over the last 2 years or so it has had an intermittent strange brake rubbing noise like a calliper piston not retracting or something. It always goes away after a few miles. Our local independent has checked the brakes twice and pronounced them to be fine and no MOT comments. Having seen the video I think its very likely the same issue albeit with different symptoms.

[myglaren]

Changes made.