Xsara Picasso brake problem

citroDane · Post by **citroDane** » 07 Feb 2011, 21:09

Hi everyone,

I'm trying to help a friend who has a strange and rather dangerous problem with the brakes on his 2005 Xsara. Once every few days or so the pedal feels hard and the cars brake capability drops to ca. 10-15%...very scary.
Once I was with him in the car when it happened and he told me, this time the pedal didn't feel as hard as the other times but the car wasn't really braking -just the same.

I myself believe the root cause might be a defective master cylinder. Other than that I can think of no other culprits. So I thought I'd post the question here and see if people think I'm on to something or if anyone has a different take on this.

Thanks a lot in advance,
Gabriel

nick · Post by **nick** » 07 Feb 2011, 22:16

Is it petrol or diesel?

I've had this problem on a diesel Xsara and it was caused by the brake vacuum pump sticking.

P616VKX · Post by **P616VKX** » 07 Feb 2011, 22:18

I had this on my Pic' HDi 90...

No idea what caused it, it would have a day or so of doing it, then all of a sudden, the brakes would work beautifully.

nick · Post by **nick** » 07 Feb 2011, 22:30

With mine I even had a main dealer look at it, who could find nothing wrong.
After putting up with it intermittently for 2 years I found a suggestion on another forum to try spraying WD40 into the brake vacuum pump. I did and the problem went instantly and never returned in the following year or so I kept the car.

Edit: On reflection although WD40 was suggested I think what I actually used was silicone spray lube.

citroDane · Post by **citroDane** » 08 Feb 2011, 03:04

Hi gents,

Thanks a lot for your replies. It is a petrol (1.6L 66 kW/90 PS). I reckon the brake system on this one is probably not that much differernt from yours (it might have been if there were a significantly stronger engine in it, I suppose).

Based on your replies (luckily I see I I am probably on the right track) I would start by spraying some silicone lubricator on his vacuum servo booster (vacuum pump) and hopefully that will take care of business. Do you think there is a chance the pump is defective? He's not losing any fluid so no leakage I reckon.

Cheers,
Gabriel

citronut · Post by **citronut** » 08 Feb 2011, 08:21

a petrol car does not have a vacum pump the servo gets its vacum straight from the inlet manifold/indiction,

regards malcolm

citroDane · Post by **citroDane** » 08 Feb 2011, 12:07

Interesting. Is that specific for Citroen? I am not a pro but if I am not going senile I think I recall to have seen cars with gas engines that have vaccum pumps.

citronut · Post by **citronut** » 08 Feb 2011, 12:35

the reason a diesel requires a vacum pump is there is tooooo much suck at the inlet/induction to use for a servo,

but on a petrol engine its fine,

just follow the vacum pipie/hose back to the engine from the servo, it will go to the inlet manifold,

regards malcolm

rick45 · Post by **rick45** » 25 Feb 2011, 16:50

citroDane wrote:Interesting. Is that specific for Citroën? I am not a pro but if I am not going senile I think I recall to have seen cars with gas engines that have vaccum pumps.

check vacuum pipe for blockage and also the vacuum valve on servo,
it could also be a perished rubber seal in the servo.

Post by **myglaren** » 25 Feb 2011, 20:56

citroDane wrote:Interesting. Is that specific for Citroën? I am not a pro but if I am not going senile I think I recall to have seen cars with gas engines that have vaccum pumps.

I had a Volvo 265 with a vacuum pump, operated a load of ancillary equipment.