Not so Magic Carpet ride W124

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300DT

New Member
Joined
Oct 22, 2013
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24
Car
W124 300DT
My first post!
Hi everyone, I am the proud owner of my first W124 estate having searched for a good one for almost 2 years. Now of course a 'good one' according to my criteria doesn't guarantee that I have actually found a good one as I'm not a professional spanner man and I don't have any experience with the W124.

However it's a two owner car that has just cracked 100k with every mot and and a very very good history file. Everything seams to work as it should and the body and interior are very clean including the original front wings.

The reason for my post is that it doesn't ride as I expected it to as the ride seems to be extremely sensitive to the road surface. At speed on the motorway it feels composed and reasonably quite but on poor A roads and B roads it feels jittery and certain Tarmac sends a booming hum through the interior?

The SLS appears to work ok the ride height looks spot on and there are no bumps, bangs and creaks from the front.

Could it be the spheres have hardened or something that is supposed to articulate smoothly is seized ??

There are no advisories on the recent MOT?

Any help from you guys would be much appreciated.

Thanks in advance.
 
Any tips for checking the spheres? Are they soft enough to feel the difference between hard and soft? They do compress and pressure up to adjust the ride height.
 
Olly puts a pen in and if hard they're gone. However, if you have no experience of the feel, I'd replace them anyway, they are not greatly expensive and the symptoms you describe are exactly those of spheres.
 
Thank you.
Are there any other suspension / steering components to check or replace out of good order at 100k? I might make a weekend of it and try and tick off more than one.
 
Check for play in the ball joints, check bushes and shocks all round. I suspect bushes are going to need doing - Nick Froome of W124 replaces the front anti-roll bar bushes as a matter of course.

Another component of good ride are the tyres. Nick (verified by my personal experience) sticks on Continental Premium Contacts 2s or 5s and they do ride exceptionally well.
 
Tick box for the Conti's as that is exactly what she's wearing!
Hopefully there are no special tools for ball joints and bushes??
I think I read some time ago that the ball joints are hard to spot and tricky to remove so if I'm going to go to the trouble of having her off the ground is it worth doing them anyway.
 
Bushes I believe have a special tool but I think others are much better placed to help with how to do what you need to do than me (I merely have observed - and paid for - what has been done to my three W124s and my W210 over the years!).
 
Thank you for the replies Charles, I'll look out for some other feedback.
Thanks again.
 
Hi
best test for faulty accumulators is ride quality, there is basically no damping so the ride tends to be 'crashy' rather than smoothly riding over things - if it's only one side there will probably be a lot of pitching about at motorway speeds. Also ruptured accumulators will take up a fair amount of fluid (replaces the volume where the gas was) and tend to discolour your fluid, if you take them off you can check by pushing something blunt into the accumulator hole to feel for resistance, if the diaphragm is burst = no resistance, other wise you should feel it halfway in the sphere

You can check the SLS by putting something ( or someone;) ) very heavy in the back, then starting the engine to see if it pumps the chassis back up to where it should be

Sounds more like sloppy bushes in the suspension - lots and lots of links and bushes, if they all give a little too it will add up to a lot- or possibly subframe mounts to me though.
The hum could be tyres?
got two W124 estates, love em
cheers
 
I can't see how you can really check properly gassed spheres by hand and a probe of some sort.
Fully gassed spheres will have about 50-Bar static pressure. That is an awful lot to press back by hand, especially as when the gas volume reduces, the pressure increases at the same rate.

To the O/p. The issue does sound like hard spheres and as you cannot verify the pressure left inside and you intend to keep the car, I would fit new ones.
 
At that mileage suspension stuff does start getting seized.

At front, the wishbone bushes can seize and the bolts going through them
often need to be sawn through to remove the wishbone.

Nearside goes first due to more bumps etc that side of road.

Test by opening bonnet and pushing down firstly on offside of slam panel to see if suspension is compliant that side; then press nearside and compare
to see if stiffer than offside.

If stiffer that side, then likely the front bush of the wishbone is seized to the bolt going through it.

Reason for opening bonnet is that you can often hear the seized bush protesting when pressing down.

AT rear of car, the tie rod that is adjustable for toe, will seize after high miles.

Again its the bush and through bolt seized together, and will need to be cut through to remove.

Both these problems will have some adverse effect on proper tyre wear, so do check across whole width of each tyre, to see if there is the start of adverse wear.
 
Surely it doesn't matter if the bolt seizes inside the bush, as the bush should be trapped tightly into the retainer anyway. The rubber does the twisting, not the bush.

My guess is still worn out spheres. If the car has a towbar, stand on it and jump up and down on it. If the back end gets stiffer quickly, the spheres are shot.
 
Guys this is great stuff, I've been bouncing and pushing and all sorts.

From what you've advised I'm going to guess for the near side sphere as it pumped up quickly when I bounced on the tow bar but when jumped into the back and tried left and then right the right movement was nice and pliant but the left side felt quite firm. Near side of car does feel firmer on the under bonnet bounce test.

I'll check those wishbone bushes / ball joint etc as the outside of the near side tyre is worn excessively whilst the middle has 6mm so either the previous owner only ever turned right or something isn't happy.

Loving the car already though and today I've discovered another gadget, orthopaedic drivers seat!! Didn't even know it was there and it works.
 
As a matter of interest where are you located. I might want your old spheres as a test set to make an adapter for this...


Rearcentresphereontest.jpg
 
I'm close to Southampton?
Ok perhaps I should know but I don't. I'm guessing it's to test the spheres ... But if not what is it?
 
Yep. It's my home made sphere tester. I haven't made an adapter for Mercedes spheres yet, but might.
There isn't much demand for testing Mercedes spheres as most people don't know they are going hard until it is too late to save them.
I suspect your left sphere is ruptured.
 
I'll let you know when they're both changed and if you're too far away to collect I'll stick them in a box and send them.
 
Guys this is great stuff, I've been bouncing and pushing and all sorts.
From what you've advised I'm going to guess for the near side sphere as it pumped up quickly when I bounced on the tow bar but when jumped into the back and tried left and then right the right movement was nice and pliant but the left side felt quite firm. Near side of car does feel firmer on the under bonnet bounce test.
I'll check those wishbone bushes / ball joint etc as the outside of the near side tyre is worn excessively whilst the middle has 6mm so either the previous owner only ever turned right or something isn't happy.
Loving the car already though and today I've discovered another gadget, orthopaedic drivers seat!! Didn't even know it was there and it works.

"outside of the near side tyre is worn excessively" - been told that's alignment ie camber wrong

http://www.peachparts.com/shopforum/diesel-discussion/271570-self-leveling-system-how-works-troubleshooting-system.html

http://www.peachparts.com/shopforum/diesel-discussion/193461-mysterious-inards-sls-accumulator.html

When the accumulator is off the car and empty of oil, the only pressure would be in the gas cell, retained by the diaphragm.
If the diaphragm is ruptured the will not be any gas pressure either...If you probe the gas cell you will feel the resistance of the diaphragm, if it is intact - if the diaphragm is broken, the probe will go all the way in to hit the top of the accumulator
simples
 
When the accumulator is off the car and empty of oil, the only pressure would be in the gas cell, retained by the diaphragm.
If the diaphragm is ruptured the will not be any gas pressure either...If you probe the gas cell you will feel the resistance of the diaphragm, if it is intact - if the diaphragm is broken, the probe will go all the way in to hit the top of the accumulator
simples

What you say is true for a ruptured accumulator, but normally you can tell as it continues to spray oil out for some time after removal, due to the oil having passed the diaphragm and being ejected under the air pressure behind it.
In addition, a ruptured sphere membrane doesn't even fill the inside of the sphere, so can be seen as no good.

Once the diaphragm is ruptured, the sphere is toast.

There is no method of testing a good sphere by probing by hand, you need to know the actual static pressure.
No-one tests Mercedes spheres or is that familiar with the system, so they all end up getting ruptured eventually.
 

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