Citroen C5 HDI '06' reg. - Hard brake pedal on 1st start up of the day

Honest John Back Room » Technical matters
View Threaded
Sat 26 Jul 2014 09:49
Citroen C5 HDI '06' reg. - Hard brake pedal on 1st start up of the day - thedadda48

So, I get in the car for the first time that day, start her up and the brake pedal is rock hard.

Sometimes, if I wait long enough, it sorts itself out. But usually I have to turn it off, restart and wait a while.

When in this state, if I drive off, I have very little power from the engine. A bit light an old stromberg carb with a pin hole in the diaphram is the best way to explain it.

My local guy thinks it's the ABS pump, "and that is expensive".

Would really appreciate some feedback please, thank you.

Reply | Report as offensive | Link
Sat 26 Jul 2014 10:08
Citroen C5 HDI '06' reg. - Hard brake pedal on 1st start up of the day - bathtub tom

I'd look for a leak on the vacuum side of the brake servo.

The symptoms would suggest to me the brake servo's losing it's vacuum overnight and taking too long to restore it as the engine's started due to the induction side having an air leak.

Reply | Report as offensive | Link
Sat 26 Jul 2014 11:57
Citroen C5 HDI '06' reg. - Hard brake pedal on 1st start up of the day - Ordovices

Is the servo not powered by a vacuum pump rather than the manifold depression?

Reply | Report as offensive | Link
Sat 26 Jul 2014 12:40
Citroen C5 HDI '06' reg. - Hard brake pedal on 1st start up of the day - thedadda48

Hi there. yes it is. And a new pump will be gambled on.

Many thanks.

Reply | Report as offensive | Link
Sat 26 Jul 2014 12:42
Citroen C5 HDI '06' reg. - Hard brake pedal on 1st start up of the day - Peter.N.

It does indeed use a vacuum pump. Check the pipe from the pump to the servo it could well have a leak, alternatively the pump or servo unit could be under par.

Reply | Report as offensive | Link
Sat 26 Jul 2014 12:39
Citroen C5 HDI '06' reg. - Hard brake pedal on 1st start up of the day - thedadda48

Thank you very much for your response. My thoughts as well.

It does seem as though the pedal 'comes back' progressively when correcting itself.

I think the new pump on Ebay is going to be purchased.

Reply | Report as offensive | Link
Sat 26 Jul 2014 14:30
Citroen C5 HDI '06' reg. - Hard brake pedal on 1st start up of the day - bathtub tom

Whoops! That'll teach me to learn model designations. I should've realised it was an oiler from the HDI.

Reply | Report as offensive | Link

Looking for a garage you can trust? Honest John's Good Garage Guide has thousands of reader recommended garages, plus how-to guides and tips on servicing.

The Good Garage Guide

Will you have to pay the low emissions charge?

Use our ULEZ checker to find out if your vehicle is subject to ULEZ charges. Simply enter your number plate into the Honest John ULEZ checker to see if you will have to pay to enter the London Ultra Low Emission Zone.

Check your vehicle