Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: sophos9 on 02 September 2008, 18:44:13

Title: Rear Suspension Gone Solid?
Post by: sophos9 on 02 September 2008, 18:44:13
I have the stupid air suspension thing on the rear and have noticed that going around round-a-bouts and stuff, any flick on the throttle can send the back flying.

Checked the rear today and noticed that its pretty much rock solid. I replaced the rear shocks with genuine GM parts not even 15k ago. For a while, I did disconnect the airpump thing in the front.

Can someone advise if they are breaked or not (or how I can diagnose pls)

Thanks
Title: Re: Rear Suspension Gone Solid?
Post by: sophos9 on 02 September 2008, 19:44:25
oh bugger, have I messed up?

When I installed the suspension (approx 15k miles ago), all I dont was put the self levelling suspension on and that was it.

Just looked it up on the TIS and it states

"Vehicles with vehicle level control: Note installation position of pressure line connection. Charge new shock absorber slightly with compressed air. Raise vehicle. Install pressure line connection on shock absorber."

Never done that  :-[

How do I add compressed air to them, where do I do it?

Thanks
Title: Re: Rear Suspension Gone Solid?
Post by: Matchless on 02 September 2008, 20:00:14
Are you saying that the suspension is stuck at maximum height? If so its likely to be a problem with the level sensor. For a tempoary fix you can unplug the compressor (or pull a fuse, but dont know which) then release the air hoses from the shocks to lower the suspension.
Title: Re: Rear Suspension Gone Solid?
Post by: sophos9 on 02 September 2008, 20:12:21
Not stuck a max height, its just solid!!

Just been out, jacked each side up in turn and pulled the air connector. One sound gave a loud hiss, the other gave nothing. Checked the state of the connectors and saw that one side does not have a rubber 'o' ring (the side that did not hiss)

This also would explain why one side sits higher than the other (side that hissed is sitting higher)

What would happen if I just unplug the rear connectors and pull the fuse? Will the rear suspension get messed up?

Thanks
Title: Re: Rear Suspension Gone Solid?
Post by: sophos9 on 02 September 2008, 21:17:39
Rear feels a bit softer after doing the above.

Can some help with what I should do next? What happens if I pull the suspension connector and the pump fuse? Will the rear suspension still work ok or would I need to buy 'normal' rear shocks?

Thanks in advance
Title: Re: Rear Suspension Gone Solid?
Post by: Entwood on 02 September 2008, 21:31:23
By the sounds of things all you need is a new o-ring !!

Sounds to me like one side leaks the other doesn't... so try and sort the leak and they'll both work as designed :)
Title: Re: Rear Suspension Gone Solid?
Post by: sophos9 on 02 September 2008, 22:07:55
That correct...

Just ordered a box of variable size o-rings - will fit when they arrive.

Can someone confirm what the TIS instructions are "Vehicles with vehicle level control: Note installation position of pressure line connection. Charge new shock absorber slightly with compressed air. Raise vehicle. Install pressure line connection on shock absorber."

How do I charge it, where do I charge, what happens if I dont charge??!!  :'(  :-/
Title: Re: Rear Suspension Gone Solid?
Post by: Entwood on 02 September 2008, 22:17:11
AFAIK the reason for the initial slight charge is twofold, to "release" the unit if it stuck due to non-use whilst stored, and to make fitting slightly easier. Once its fitted, as in your case, the compressor should be sufficient to inflate it correctly.

My process of checking would be ...

1) with line disconnected, is compressor running and air coming from the line ? - thus checking compressor

if so

2) with line connected shocks fully down .. do they try to inflate, are there any noticeable leaks.. in your case .. especialy from o-ring area

if they do

3) does a manual tweak of the level sensor cause the levels to change ?

HTH
Title: Re: Rear Suspension Gone Solid?
Post by: sophos9 on 02 September 2008, 22:25:48
Thanks for the help, thats makes sense.

Compressor is functioning, tested that not so long ago  :y

Seal is missing on driver side (which always looks lower than the passenger - makes sense as its losing height due to the leak)

Passenger side seal looks a little bit suspect - will replace both when o rings arrive.

Have not tested the level sensor, will test that when the seals are correct! Will the level sensor change the ride height at any time whilst the vehicle is in operation?

Thanks mate!!
Title: Re: Rear Suspension Gone Solid?
Post by: Entwood on 02 September 2008, 22:31:03
IME ( both this mig and the last one) the level sensor/compressor only works for about 1 minute or so on initial start, and does what it says .. pumps up to level (and when I have the fully laden 'van on the back and a bootfull of stuff for 18 days in France it has some work to do !) after which it stops. I've never noticed it running whilst travelling .. it really has no need to.

IMHO it is a great system, with the amount of towing I do it is invaluable.

I wonder if your "lockup" is due to one side only inflating .. thus upsetting the whole balance of the car

HTH
Title: Re: Rear Suspension Gone Solid?
Post by: sophos9 on 02 September 2008, 22:33:23
Thanks for the help, as always - will post up I get it sorted!

Cheers
Title: Re: Rear Suspension Gone Solid?
Post by: sophos9 on 03 September 2008, 10:42:08
Just a quick update. Really think I'm on not nailing the root cause for the strange handling with the barge.

It wanders all over the place, bad around corners - hard to turn left and right hand turns can skid the rear pretty easily. After I dropped the shocks and released the pressure, the passenger side was much more pumped that the right which had no pressure due to the seals.

Today, the handling is much different - smooth cornering and very little wander.

I'm guessing that due to one shock being pumped right up and the other not being pumped at all would cause some strange behaviour in the handling?
Title: Re: Rear Suspension Gone Solid?
Post by: Andy B on 03 September 2008, 10:51:51
Quote
.....
I'm guessing that due to one shock being pumped right up and the other not being pumped at all would cause some strange behaviour in the handling?

Unless there's another problem with the dampers, both have the same pressure in them as they are linked together via a 'T' piece some where around the rear axle.
Title: Re: Rear Suspension Gone Solid?
Post by: sophos9 on 03 September 2008, 10:54:11
Thanks mate but as stated earlier in the post, the problem is with the pneumatic pipes shock side, one has a sealing o ring on it (passenger side), the other does not have an o ring therefore never holds any pressure!!
Title: Re: Rear Suspension Gone Solid?
Post by: Andy B on 03 September 2008, 11:01:30
Quote
Thanks mate but as stated earlier in the post, the problem is with the pneumatic pipes shock side, one has a sealing o ring on it (passenger side), the other does not have an o ring therefore never holds any pressure!!

That's what I mean though, if you have a leak at one shocker, then you have a leak on both because they are linked togther via the T piece in pipework. That's why you got a hiss of air escape from one side, but not the other. I can't now remember how they fasten to each shocker but the pipes can be bought from Vauxhall ..... at a price.
Title: Re: Rear Suspension Gone Solid?
Post by: sophos9 on 03 September 2008, 11:12:52
Sorry mate, I understand what you are saying now. So as one side is not holding pressure, the entire system should not hold any.

If this is the case, how come the side that has a seal is pressurised (unless of course there are check valves inline?)

Thanks
Title: Re: Rear Suspension Gone Solid?
Post by: sophos9 on 03 September 2008, 19:49:28
Bought some o rings today, jacked up each side, removed the old, fitted the new then dropped car back down.

Once done, started car - heard compressor, drove car on level ground and measured the distance from the floor to the arch.

F N/S - 26.5inch
F O/S - 27inch
R N/S - 27inch
R O/S - 27.5inch

Previous, the rear near side was about 1.5inches higher than the rear off side. Will measure the distance again tomorrow. If there is a leak, I would expect to see a difference...