s600owner

Hi,
I was changing wheels yesterday. With the front wheel off the car. I noticed that on the front left (passenger side) I could move the ball joint up and down with my hand (the balljoint is situated at the base of the upper control arm/wishbone and slots into a vertical metal slightly curved silver coloured rod. This ball joint is then screwed into the metal rod via a nut).

I am sure other owners have experienced this. My car had the front right control arm replaced under warranty around 16,000 miles ago. The current mileage is now 46,000m. I now do not have any warranty.

Please would it be possible to offer some advice. First It costs £208 to just replace the ball joint and costs £500 to replace the complete upper control arm. This includes parts, labour and VAT tax. Which option would you go for?

Secondly, is this dangerous or can I put off the repair for two months, as I do very little mileage? I only notice slight vibration through the car when travelling at 65mph to 75mph.

dragonrt

you should replace the ball joint. I had it replaced on the front passenger side last month after hearing squeaking noise from the front suspension. It cost me $350USD to fix it.

s600owner

Hi,
I need help with this major problem, please.

I have just replaced the upper control arm on the front passenger side. I went out for a test drive and when I parked on my level driveway I noticed that the front is now lob-sided!

I have the ABC suspension and even when I raise the suspension from within the car the front is still lob-sided.

With the suspension raised to the maximum level, on the driver's side I can fit 4 finger widths between the top of the tyre and the wheelarch. But on the passenger side where the control arm was replaced, I can only fit 2 finger widths between the top of the tyre and the wheelarch.

With the suspension raised to the normal level, on the driver's side I can fit 2 finger widths. But on the passenger side where the control arm was replaced, I can not even fit 1 finger widths.
Please help !!

mugsy415

Don't put off the repair. And If I were you just replace what you needs to be done (Just the ball joints). It costs too much money with these cars if something else goes wrong because of a hesitation. Bite the bullet before one bad thing leads to another!

mugsy415

I guess I shouldve read the your last post sorry

s600owner

Hi,
Now not only is the front passenger side is down but also the rear passenger side is also down!

I have taken it to a main dealer and they carried out a complete rodeo check. They say there is no fault in the system, but visually they can see that the passenger side front and rear are down by two inches!

Please does anyone have any ideas?

winmaw

It happened to me once. You should ask the mechanic who installed this to look at the electrical connectors properly. My case was the mechanic unplugged the connector while installation and forgot to plug it back.

s600owner

Hi Winmaw,
Do you know which connectors specifically would control the level of the vehicle when stationary or on the move?

For the ABC system, there is a metal rod screwed into the upper control arm. This I think controls the level of the front left passenger wheel (not sure..).

whoover

Are you saying the MB agent can't fix it, even though they see the suspension is 2 inches off? I would say you need another agent. It could be a valve block. It could be a lot of things. But you need to let someone competent diagnose and fix it.

Ausmbtech

If the level sensor isn't correctly located on the upper control arm then it sends false readings to the airmatic or ABC control unit. The lop-sided vehicle "looks" level to the computer and therefor leaves no fault code.

Recheck the sensor position (not the control rod) on the upper control arm.

s600owner

Thanks for your reply.

My S600 is now back with a mercedes main dealer. I will contact the shop manager and let him know that he should check the correct fitting of the sensor (which looks like a black box underneath the left arm of the upper control arm).

But why would one level sensor on the front passenger side also cause the passenger side rear to also drop by the same amount?

s600owner

Hi,
The merc main dealer has advised that my S600L requires a new front pressure relief control valve and a complete ABC filter and hydraulic fluid flush. This will now cost me £915 to put right!

Apparently this is not related to the control arm I replaced and could have happened at anytime, due to microscopic metallic pieces found in the ABC fluid ending up in the front control valve.

There is also a rear control valve, which should not be affected after the flushing.

The MB dealer has guaranteed the control valve part for a two year period.

Painful as it is to be paying one's own money, I guess this goes with the territory of owning a flagship merc with the latest advanced technology.

I now hope I can drive my German bullet worry free for a few more years to come!

whoover

The valve block is a common failure point for ABC. That's why it was my first guess in the post yesterday.

koreanpers

my dealer replaced the ball joints for free, but i have the starmark warranty

whoover

BTW, in the US we have a recall for an ABC failure:

https://mbworld.org/forums/cl-class-w215/200314-flushing-abc-changing-filter.html#post2339358

I know that typically European owners are left to twist in the wind on such defects, but you should have your dealer check for this corrosion, common in early W220 ABC-equipped vehicles.