Citroen C5 diesel brake vacuum pump

[petrolhead63]

my facelift 2.0 hdi estate brake vacuum pump is lazy on cold start up. I have tried using "posh" oil and other logical things like taking the face plate off the pump and checking the rotor/vane part/cleaning but now need to look further.

I have proved the fault by removing the vacuum suck pipe directly off the pump first thing on a chilly morning and putting on a vaccum gauge before starting the engine. It can run for some considerable time before registering any vacuum. Once the car has started and given vacuum you can turn it off and start it getting immediate vaccum on the gauge.

before I buy a new pump are there valves and things I could clean on the engine side of the pump if I remove it? or anyother common easily cured issues known. It is noticebably less of a problem on a warmer morning!

Thanks for any help offered.

[nick]

I had this on my old Xsara HDi and improved it by spraying some silicone spray lube directly into the pump. I don't know if it cured the problem completely as I sold the car later in the year, and like yours it only seemed to give trouble on cold mornings, but it certainly worked fine for the rest of the winter after that.

Mine had the 110 engine and the lack of brake servo was coupled with lack of boost as the turbo wastegate is operated by the same vac pump on those! Is yours a 90 bhp?

[petrolhead63]

thats interesting, did you spray it through the vacuum pipe connector? No mine being facelift is the not so nice 138bhp pepped up one. I had a pug 406 with the 110 hdi for 6 years which was far better and ran faultlessly to 269K when someone decided to park their VW polo on top of it o the verge outside my house

As for affecting turbo boost the brakes are scary with no boost at all so wait until it comes up or only move slowly

[nick]

Yes, with the engine running I just unclipped the vacuum pipe from the pump and sprayed the lube straight into the nozzle on the pump so it sucked it in. It had been getting progressively worse for about 3 winters before that, and was particularly bad in very wet weather. The first winter when it happened a Citroen main dealer had the car for a day and could find nothing wrong with it (!) The spray lube seemed to improve things instantly and the brake servo was fine for the remaining 6 months I owned the car.