Bleeding SLS on w123 estate

[stuarth]

I have rear SLS. I have just changed the spheres and fluid. I had heard the SLS is self bleeding and if so, how long does it take? I ran the engine for about a minute and bounced up and down in the rear but it is still low at the back. If it isn't self bleeding, how do you do it?
thanks

 

[Dieselman]

Either load the back up with some weight or go under and manipulate the valve linkage.

 

[millo777]

Standard DIY procedure seems to be put the car onto ramps and move the height selector on the levelling valve through high to low a couple of times.

When I had the spheres replaced on a w140 it took a couple of days for the rear suspension to settle down. I assume this was due tot he self bleeding.

 

[jaymanek]

there is no better method than to drive it around, it will bleed itself.

 

[stuarth]

Seems ok now but I still have a banging sound from the rear passenger side. I thought this was due to the spheres being split inside. Incidentally, when I emptied the system via the purge at the back, the liquid which came out was like milk - it turned into a clear brown liquid when it settled but was clearly mixed with air.
So, could this banging be coming from one of the the hydraulic rams being duff? There is no sign of any movement in any of the suspension joints and since the car only has 80k miles from new (albeit in 30 years..), nor shoudl there be.
The ride is a bit softer anyway now I changed the spheres so there must have been some problem but I can't explain this bang. Any clues?

 

[jaymanek]

banging wont be caused by spheres... take a look at the struts themselves or the anti roll bar links (plastic and often break) and also the mounting points for the anti roll bar.

 

[stuarth]

Oh dear I am embarrassed...
I changed the links (30 minutes to do both sides) and the banging I have had for a few years has GONE! What is remarkable is that the amount of play on the joint from the link to the axle was just perceptible by feel - very little indeed.
Anyway it has gone. I probably need to do the roll bar mounts too. The spheres have made the ride a bit nicer and it has levelled itself. All in all, I am pleased. Thanks for the advice everyone!

 

[stuarth]

There no polite words....
Changed the links and the moutings and there was a 100% improvement. A week later it is banging again! I thought that maybe I had not tightened things enough but I rechecked.
Any clues what is next to change?

 

[jaymanek]

Well if it went by changing the links your problem is related to the rear anti roll bar... you sure the mountings havent sheard off?

 

[sceh]

After waiting ages for new roll-bar bushes, I changed them and the problem is exactly the same! If the car were in worse condition I would scrap it since I have better things to do but it is mint :-(

 

[sceh]

Are the spherical accumulators for the suspension pressurised for life or do they leak and need to be pumped up now and again?

 

[a111r]

They're filled with Nitrogen and they leak when the rubber diaphragm perishes.
This turns the SLS fluid 'frothy' and the main reservoir level drops as the fluid fills up the space in the spheres.
Only solution is to buy new ones.

 

[sceh]

Thanks - i'll check since I don't have a pressure kit.
Any idea how to check or adjust the height? The manual says not to use the connection rod...

 

[alabbasi]

You should consider flushing the fluid, it will bleed the system at the same time. Siphon what's in the reservoir and add fresh fluid then run the engine with the return hose disconnected and directed to the bottle. Once the fluid comes out clear, you have fresh fluid that has cycled through the system.

 

[a111r]

Thanks - i'll check since I don't have a pressure kit.
Any idea how to check or adjust the height? The manual says not to use the connection rod...

IIRC it's done by re-positioning the lever on the SLS valve spindle.

 

[sceh]

I despair..the fluid is clear and has not gone down but it is no surprise since the accumulators were changed about 2000 miles ago (ten years...)

 

[sceh]

OK. Purged, new fluid, new filter, bled by operating the lever but the noise is still there occasionally.
The only thing I can think of is the struts or springs.
Has anyone removed struts? How easy is it?
thanks

 

[sceh]

btw, the car seems to roll when I go round a roundabout - more than my other cars. ANy ideas here?