xm suspensio

crooser · Post by **crooser** » 22 Feb 2004, 15:24

i am doing up an xm estate that was standing for about 6 months.the suspension was very slow to come down from max height at the rear with lots of creaking and groaning.now the rear won't come down at all, although the front comes down normally. any ideas anyone?

crooser · Post by **crooser** » 22 Feb 2004, 15:26

add an n to suspensio for me.

noz · Post by **noz** » 22 Feb 2004, 15:40

crooser,
2 choices really, either rusty height corrector linkage or rear swinging arm bearings.
Linkage is easy to sort witha combination of wire brush and WD40.
Rear swinging arm bearings are a peach. I have done them many times on the CX and my XM 2.5TD. The hardest part of the job is getting the spring steel pin which holds the strut to the arm retracted from the swinging arm. The pin is steel and the arm alloy. They 'rust' together and are a pig to get out.
cheers
noz

crooser · Post by **crooser** » 22 Feb 2004, 16:10

noz.i'll try the easy one first.i tried the arm once on one of my old safaris and gave up

crooser · Post by **crooser** » 22 Feb 2004, 18:06

noz,i did the easy one and took off the height corrector-nothing wrong with it.the back end is still up and solid,last night i took the car out for a test run and the suspension was more or less ok -i've had worse on a citroen.the problem arose when i set maximjm height this morning.am i correct in saying that once the height corrector is removed there should be no pressure in the rear or does the anti sink keep it up?

AndersDK · Post by **AndersDK** » 22 Feb 2004, 19:22

Hmmmm...
To release the suspension pressure on antisink/HA suspension fitted models - you need to have engine running while you set the height control to lowest.
This is because the antisink valve closes off the rear suspension - when no system pressure present from running engine/pump.
The antisink valve has in fact a double circuit - isolating the rear suspension from it's HC - and the system pressure from safety valve to HC.
That's why the suspension kept up even removing the HC - and you did'nt observe any pressure weezing out despite the raised rear.
In other words : as soon as system pressure is lost (& main accumulator spare pressure exhausted) - the height controller won't work.
Opposite : if the main accumulator is in good nick, you will still have some pressure available to alter the suspension height right after engine stop. But soon the main accumulator spare pressure is exhausted - making the safety valve shut off - and then the HC won't work anymore - as no system pressure is present to keep the antisink valve open.
I know - it's food for LHM "heads" [8D]
But once you understand the basics - you also learn to recognise normal & abnormal behaviour in general terms.

noz · Post by **noz** » 22 Feb 2004, 19:27

The anti-sink will keep it up if the engine is not running. If the engine is running and the pump is producing pressure, the pressure equalises across the electrovalve and allows the excess fluid back to the tank as determined by the height corrector.
If you have access to a pit or ramps - try this:
Disconnect the little plastic arm on the height corrector. Using a screwdriver or other such implement move the little lever on the HC in and wait. The car should rise. Move the little arm out and wait. The car should fall. Do this a few times to get the hang of it. This proves the HC and associated hydraulics. If it works then the problem's with the link between the HC and the anti-roll bar. IF it still doeasn't behave there's something wrong with the HC or something else. If so, there are others on this forum who know more about that than me.
cheers
norrie

crooser · Post by **crooser** » 22 Feb 2004, 19:34

anders,i understand what you mean and i am not arguing.the car was at normal height and i raised it to max and switched off.i then did some work and lowered it right down.the front sank but not the rear.i then depressurized[without the engine running unfortunately] and then i removed the rear HC thinking that it was faulty-it wasn't.so,the problem was there before depressurization.i hope you can work this out

AndersDK · Post by **AndersDK** » 22 Feb 2004, 20:20

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by crooser

anders,i understand what you mean and i am not arguing.the car was at normal height and i raised it to max and switched off.<hr height="1" noshade id="quote"></blockquote id="quote">
You mean switched off (stopped) engine ?
<blockquote id="quote">quote:<hr height="1" noshade id="quote">i then did some work and lowered it right down.<hr height="1" noshade id="quote"></blockquote id="quote">
Here you mean a time delay by other works you did after stopping engine - before you moved the height controller to lowest ?
<blockquote id="quote">quote:<hr height="1" noshade id="quote">the front sank but not the rear.i then depressurized[without the engine running unfortunately]<hr height="1" noshade id="quote"></blockquote id="quote">
- the usual PR pressure relief screw depressuring ?
<blockquote id="quote">quote:<hr height="1" noshade id="quote"> and then i removed the rear HC thinking that it was faulty-it wasn't.<hr height="1" noshade id="quote"></blockquote id="quote">
- no [:)] - because if YES to my above questions - this is the normal system behaviour [;)] - the antisink VALVE keeps up the rear suspension.
<blockquote id="quote">quote:<hr height="1" noshade id="quote">so,the problem was there before depressurization.i hope you can work this out
<hr height="1" noshade id="quote"></blockquote id="quote">
Right - the original problem with a high rear ? - as I seem to have lost track with your original problem - sorry [:I]

crooser · Post by **crooser** » 22 Feb 2004, 21:25

anders.this is exactly what happened and the rough time delays.last night i drove the car and it drove ok.it was then put in the garage overnight and this morning i started the engine to raise the height to max.i spent about an hour working on it and then lowered it right down without starting the engine.the front lowered immediately but the back stayed up,after about another hour it still hadnt gone down and then i think that i wrongly decided that the HC was faulty.i undid the pressure relief screw with the engine not running and then removed the HC which was ok.by reading your replies again and again this is what should happen.but why did the front go down? i thought that the front was controlled by the anti sink as well?