The hydraulic pump is driven off the crank pulley Matt, along with the alternator and if fitted, the aircon compressor. In a hydraulic Citroen that pump does both suspension and power steering...MattBLancs wrote: 11 Nov 2022, 14:45I was going to say "the vacuum pump is for the brake servo in a normal car" then remembered about the funky brakes (runs off the central hydraulics? = No servo booster required?) and then you mentioned vacuum operated sunroofs and I realised that I am likely well out my depth!CitroJim wrote: 11 Nov 2022, 13:47
Then again, ask yourself if what the vacuum pump runs is actually needed any more... I know on many Xantias the vacuum pump drives nothing more than the EGR valve and the cold fast idle actuator on the pump. Both those systems often ceased doing useful work long in the past so the vacuum pump was really quite surplus... Early Xantias with waxstat fast idle actuators didn't even have a vacuum pump! I'm not sure on the BX if it might do something more exotic like operate a vacuum sunroof or the like...
What's the hydraulic pump for the suspension driven from, thought that would be off this cam pulley?
Sone sunroofs of the period, notably on the 205, used vacuum to deflate the rubber sunroof seal so the roof could open...
