Problem with self levelling suspension on 200TE 1989

[Big Jim]

Hi Guys,

Looking for some help please. Apologies if this has been answered before, I've had a search around and found some useful stuff but none of it appears to be related exactly to the snag I have.

With the engine off the rear of the car sags. After engine start I have to wait a good 60secs for the suspension to level itself.

I'm guessing the self-levelling system works otherwise it wouldn't rise after the engine starts, therefore I'm assuming the springs are shot.

Would you agree?

Oh, I should mention, the guy who had the car before me, whacked the underside of the car on the ferry. He said he had to drive with the self-levelling not working for sometime. Eventually when he repaired the levelling valve and the self-levelling system began to work, the problem with the sagging with the engine off remained.

Any comments or help would be appreciated.

Cheers

Jim

 

[andy_k]

My guess is that the self levelling valve is knackered.

located above and slightly to the rear of the drivers side rear wheel it's a little aluminium bodied valve with three hydraulic pipes and a linkage connecting it to the anti roll bar (which governs the height it opens and closes at)

If you are lucky, it's just the linkage that's broken and this will become apparent as soon as you locate the valve, if so, get a new linkage for a couple of quid from the stealers.

If you are unlucky, the valve will need wither overhauling or replacing either way you need to remove it from the car which is a messy, awkward pain of a job - it's only held on with two bolts but initially they are hidden by the hydraulic pipes (which due to their location will almost definitely be rusted solid) and once you have disconnected the pipes, everything is covered in really sticky hydraulic fluid.

if you go for repair rather than replacement, which of course may not fix the problem try this part number - MA000 586 00 32 N/STK Repair Kit at £37.03. However, be prepared for blank faces at the dealers as they would rather sell you a new valve (costs about £150) than source an awkward to find part.

Alternatively you could drop Ian Walker a PM and see if he still has the complete valve on the estate he is currently breaking.

HTH

Andy

 

[Big Jim]

Superb andy,

That gives me some really solid stuff to go on. Thanks mate.

Are there any dangers in driving it as is for a while?

Jim

 

[andy_k]

Are there any dangers in driving it as is for a while?

Jim

none that I know of, my old one used to do it intermittently over an 18 month period when the ball bearing (that's all the seal is) in the levelling valve got stuck. If anything it makes the suspension slightly more responsive

Sometimes a light tap with a hammer will be enough to release a sticking valve

the not so small print....

obviously if you start slapping things around with a hammer I take no responsibility for the outcome

Andy

 

[lookskyward1]

I have to differ on Andy's diagnosis, the car should sit level and square when parked, if it sags then the rear sprngs are shot/broken.

Changing the rear springs is cheap and easy to do.

Once the car is set up properly on a new set of springs, that's when you start to mess about with the self levelling which in this case sounds like it is working OK.

 

[andy_k]

I have to differ on Andy's diagnosis, the car should sit level and square when parked, if it sags then the rear sprngs are shot/broken.

if the return valve in the self levelling valve remains open which is the normal fail as the ball bearing jams then there is no pressure in the system and the rear sags usually by an inch or two - the hydraulics provide assistance even under normal load.

Of course it could be worn or broken springs but they'd normally result in the car not sitting level.

Andy

 

[Big Jim]

Thanks chaps,

Latest: I've checked the valve visually and the arm is in place and secure.

Is there anywa of telling whether the valve or the springs are the culprit. any tests etc.

Once again, thanks for the help.

Jim

 

[Big Jim]

Anyone?

 

[Dieselman]

I have to differ on Andy's diagnosis, the car should sit level and square when parked, if it sags then the rear sprngs are shot/broken.

Changing the rear springs is cheap and easy to do.

Once the car is set up properly on a new set of springs, that's when you start to mess about with the self levelling which in this case sounds like it is working OK.

I agree here.

The car should sit level with either the engine off or no load in the car.
The self levelling is exactly that...A self levelling device.

With the car level on the springs the level control valve linkage should have free play. Only when the rear of the car goe down should the valve allow fluid into the rams.

 

[Big Jim]

Thanks for that....

So it seems we are all agreed there is definitely something wrong with either the springs or the valve.

Is there anyway to tell which one is the culprit or is it going to have to be changing one at a time?

 

[andy_k]

The hydraulic system isn't just an addition, it's an integral part of the suspension system and as such is "active" all the time. If it worked how Dieselman and Lookskyward are suggesting with free play at rest then it would suddenly have to spring to life every time you hit a bump whilst the car was in motion.

The way the system was explained to me was that the hydraulics and springs share the load under normal conditions with the self levelling valve retaining enough fluid in the system to keep the rear of the car supported and "sprung" so it seems logical that without any hydraulic assistance then the rear should sag - this being supported by a noticeable drop in the rear suspension when the system is drained to change the spheres even with known "good" springs.

The 60 seconds you mention is an inordinately long time for the system to level the car it should right itself the moment you start the engine.

I still suspect that the valve is the culprit but it is genuinely a difficult call to make as the symptoms could easily be attributed to either so by all means have a look at the springs and check if there is any sign of damage, the heavy impact you mentioned could easily have snapped the lower coil off although these earlier W124s are not known for having weak springs. So if the springs look OK then I'd go for the valve.

Andy

 

[Big Jim]

Thanks Andy

Great explanation.

Time to get the car to the garage I think.

Cheers

Jim