Depressurising hydractive with anti sink while up on stands

red_dwarfers · Post by **red_dwarfers** » 19 Apr 2011, 10:07

Going to be making a start today on the XMs belts and will be replacing a couple of seals on the hydraulic pump while everything is off.
My query, when setting up for taking the belts off I stuck it up on service high, whipped the stands underneath then jacked up until the wheels where clear of the ground. When I come to take the hydraulic pump off, bearing in mind that I'm working with hydractive with an anti sink setup here (came quite late on in the XMs life it seems). Can I set the suspension in service low while the front is up on stands and wheels off the ground and turn the bleed screw a touch to depressurise the system or does the car HAVE to physically be as low as it can go?

I've just had a look on the CXM forum at the location of the anti sink sphere. This WILL be interesting...

Xaccers · Post by **Xaccers** » 19 Apr 2011, 10:14

Kev, what's this talk about jacking it up?
Let the car do the work!

Set it on high, slip axle stands under the front jacking points (ok you may need to jack on the subframe a bit to lift enough to get the axle stands under), then set it on low, remember the car will pivot on the axle stands lifting the front up, then depresurise.

Not that I think you need to depressurise to remove the pump's pipes, but I could be wrong, and it's better to be safe than sorry.

The car doesn't have to be low on the wheels, that's only if you want to empty the system as much as possible.

Post by **CitroJim** » 19 Apr 2011, 10:14

Nope, that'll be fine Kev,

Always loosen the bleed screw with the engine idling as this allows the suspension circuits beyond the anti-sink valves to depressurise to an extent too...

You'll find that in any case opening the bleed valve will depressurise all except a little behind the suspension spheres beyond the anti-sink valves. You'll have no worries about removing the pump..

AndersDK · Post by **AndersDK** » 19 Apr 2011, 13:53

There is no need to bleed the suspension pressure.

As Jim says : "most" of the the suspension pressure will be released, once the regulator release crew is opened.
That is : until the sfaety valve reckons the system pressure drops below approx 100bar.
Et this point the safety vale cuts off the suspension from the rest of the circuit, no matter anti-sink or hydractive variants involved.

As you will be working on the pump only there is no need spending further efforts deprusserising the suspension.
Just release the bleed screew on the regulator - thats all.

HINT : when removing the pump feed hose (from reservoir), try immediately blank off the hose end with your thumb, then prop the hose with a suitable tool, like a tap driver or large dia drill bit etc.
This will make it much easier later on re-building the pressure, since the hose is already LHM filled ready for priming the pump.

red_dwarfers · Post by **red_dwarfers** » 19 Apr 2011, 15:45

Thanks for the quick replies. That is a very useful technique Xac though I wanted to get the body a good way off the ground ready for the infamous crankshaft pulley bolt.

I'll only be working on the pump and front accumulator for this section of work so thats ideal. Thanks for all the tips

I'm just going up to lock up the pulleys and have a go at this crankshaft pulley bolt. I am VERY glad that the belt is being replaced as you would not believe how loose it is, I'm surprised it hasn't jumped a tooth

Xaccers · Post by **Xaccers** » 19 Apr 2011, 16:08

The tilt on axle stands even on their lowest setting lifts a Xantia at the front enough for me to get under, and I'm not the smallest of people

It also leaves it low enough to get a jack under the sump to adjust the engine height should it be needed (no idea on a 2.1 XM).

If you need more space, get the car up on axle stands 1 notch up.

red_dwarfers · Post by **red_dwarfers** » 19 Apr 2011, 20:39

Cheers Xac, I'll keep that in mind for next time

Xaccers · Post by **Xaccers** » 19 Apr 2011, 20:44

It works for the back too, and when changing wheels.