strange things on my c5

[morto]

just fitted to my 2.2hdi 2002 plate new rear hydrolic ram and boot as the old one was leaking, it has the Hydractive hydraulic suspension 3+... front will rise perfect and rear will not rise , but will rise if i put the trolley jack under the back and give it a help and it will stay there, once i put it down it goes to the floor and stays there,, no leaks on the system , the front will level but the backs still on the floor, so .. sphere? or level sensor?

thanks
Andy

[BX]

A leaky boot or even a leaky piston/cylinder on the rear suspension will not prevent the rear from rising unless the fluid is really flowing out. You would have a large pool of fluid on the ground in seconds so don't waste your time. A faulty sphere likewise cannot prevent the rear from rising unless it has a major leak throwing litres of fluid on the ground. Does the pump continue to run after the front rises up? if it doesn't then I would suspect the rear height sensor. The rear height sensor is a potential divider. The fact that the rear rises after you help it the first bit may further indicate a faulty sensor. The voltages on the three wires are (as far as I remember) 5volts, ground and a voltage which varies with the height. Jack up the car and put it on stands. Disconnect the link between the anti roll bar and the height sensor. Do not disconnect the electrical connector from the height sensor. Check the voltages on the 3 wires using a sharp probe. If the sensor is faulty the centre pin usually returns no voltage. If you are getting voltage on all wires check that the voltage on the wire on the centre pin varies as you move the arm of the sensor. If the sensor is ok the and the wiring from the sensor to the suspension ECU is ok then there is a fault in the electro hydraulic block

[morto]

thanks for your reply mate iv just ordered a new height sensor just to cancel that out ,, i was told that if a sphere is faulty the rear will not raise?

thanks
Andy

[waynedance]

As far as I know BX is correct in saying a faulty sphere will not stop the rear from raising unless badly leaking.

[morto]

so its more likely to be either ..level sensor or maybe the Built-in Hydro-electronic Interface (BHI). if i get a BHI from the scrapyard can i just change it over