How to replace headlight level sensor / ride level sensor for w212 E350 (no air suspension)

[MrGreedy]

Hi Merc fans,

I've got a crack on the ball joint linkage arm of the rear level sensor that controls xenon headlight level. I bought some replacement links only, but on removal of the links/sensor on the rear passenger side (above the drive shaft) I can see that there is a crack in the sensor housing itself where it holds the securing nuts, and the balls of the ball joints are super corroded and rough. Despite a lot of trying to fettle these up, there is too much corrosion to give a smooth surface for the replacement arms.

So given the failing sensor housing, I was just thinking about replacing the level sensors, but I need some help please.

1. Are there sensors on both sides at the rear, or is it just one on rear passenger side wheel suspension linkage, and one on front driver's wheel suspension linkage? Because all it needs to understand is the pitch of the chassis to auto adjust the dipped beam? Does anyone have the part numbers for all the level sensors for my 2011 w212 E350 please, or suggestions for new units other than the £400 ones that Merc charge for?

2. Having put everything back together today, this evening my headlights are way to high, so I've disturbed something. I did fully disconnected the level sensor and unplug. I assume whatever this is, it would also be the same issue if I installed a new level sensor. How do I reset the  xenon headlights to the correct level? Can I do this with iCarsoft?

3. Everything could be removed fairly easily except the plate (and associated ball joint) that connects to the upper rear suspension arm. I could remove what appeared to be the single securing nut for the plate (pics below), but the plate appeared welded on to the upper suspension arm from how much it wasn't budging. Seeing as this plate and associated ball joint comes with a new level sensor, is there something I'm missing in removing it?

Securing nut removed from back of plate with ball joint


Front of plate with ball joint that I just cannot budge/remove

 

[MrGreedy]

I should have checked the part number on the rear sensor when I had it removed from the car, but was under time pressure and fretting about not being able to remove the plate.

How about this Metzger item?

https://www.autodoc.co.uk/metzger/15819207

 

[MrGreedy]

Sorry, bumping in the hope of some help or helpful guesses...

@Jobsworth

Apologies for shamelessly linking you in; you are a mine of useful information and tips. Thank you in advance if you have any suggestions.

The only thing I can think of is either removing the upper suspension arm and getting medieval with it (heat, drilling, 5lb lump hammer) to remove the old ball joint plate, or replacing the upper arm along with a new ball joint plate that comes with a new sensor.

 

[MrGreedy]

Rear Left Upper LEMFÖRDER Rod / Strut 36250 01

https://www.autodoc.co.uk/lemforder/7020956

You can make out the two holes in the arm where the ball joint plate should sit.
The Right hand equivalent arm (36251 01) also has the two holes depicted, but this could be for ease of manufacture rather than confirming there is a level sensor on the rear driver's side.

 

[Jobsworth]

There is a level sensor both sides on cars with air suspension. Steel sprung cars only have one. It’s possible to flip the arm over I think, so you may have done that and that’s why the headlights are high. Or the sensor has died from being disturbed. The brackets are often corroded in place. Dousing with penetrating fluid will help and judicious wiggling back and forth. I have used a bit of heat to get them out before, but be bloody careful because you are near fuel tank and other bits of flammable stuff. You’ve taken the nut off. The other bit is just a locating pin.

 

[MrGreedy]

Thanks Jobsworth.

I'll douse with penetrating fluid and leave until the weekend.

Failing that, would you recommend removing the upper arm for better access/purchase/leverage/hammering ability? The subframe was replaced last month (as is hinted at by the fresh black paint finish on the subframe) so at least one end of the arm has come off recently so I'm hoping it shouldn't be too difficult to remove and work on it on the bench.

 

[Petrol Pete]

This is what happens when one of the worlds oldest (and in the past) very prestigious car manufacturers pushes a steel screw through a hole drilled in aluminium that they know full well will be exposed to all sorts of 'weather' .

Heat and violence are your friends in this fight. I have something like this in my workshop 'flame' ****nal , creates a very intense pointed flame (with MAPP gas) that can be accurate targeted , as Jobsworth says , mind the fuel tank ! . I often see people on YouTube using basically a plumbers gas torch to heat stuff up while working on cars and always think ' what bit is that bloke actually trying to warm up ? the nut , the bolt ? or the whole frigging assembly ?

Precision Lead Welding Blow Torch with Ignitor Suitable for Propane and Mapp gas | DIY at B&Q

Leading welding torch with a fine tip nozzle for small and precision welding, soldering or brazing jobs. A 1.2m gas hose connects the torch to a CGA600 bottle adaptor to be used with Propane or for a hotter flame temperature, use Mapp gas. The adaptor also has a gas adjuster to allow control...

www.google.co.uk

 

[Drpaul10]

I have just replaced mine with a new sensor from MB (actually on a 2012 CLS 350 but same part number and same principle). I bought the whole lot as the ball joints themselves were very corroded (and the plastic arm had snapped) when I took the wheel off to check it I found that if I moved the remains of the arm then I could change angle of beam so fundamentally everything still working). Problem is , now I have changed the old sensor for the new, when you switch on, the lights do their up down dance but then still seem to be pointed quite high. Do these need a reset with star or something?

 

[Jobsworth]

I have just replaced mine with a new sensor from MB (actually on a 2012 CLS 350 but same part number and same principle). I bought the whole lot as the ball joints themselves were very corroded (and the plastic arm had snapped) when I took the wheel off to check it I found that if I moved the remains of the arm then I could change angle of beam so fundamentally everything still working). Problem is , now I have changed the old sensor for the new, when you switch on, the lights do their up down dance but then still seem to be pointed quite high. Do these need a reset with star or something?

You can get away with a friendly MoT tester who can set the beam height with the car unladen. The on board system will take over from there and it’ll be right. Certainly much cheaper than a main dealer

 

[Drpaul10]

You can get away with a friendly MoT tester who can set the beam height with the car unladen. The on board system will take over from there and it’ll be right. Certainly much cheaper than a main dealer

Ahh. So all is required is level surface and manual adjustment of both headlights? I though maybe something more 'digital' than that and star would be needed. If that's so that's great. MOT is immediately imminent so hopefully they can do it at the same time.

 

[MrGreedy]

This was my next question. I have bought a new genuine Merc level sensor, but haven't fitted it yet for fear of needing to get it recoded.

The lights are currently working fine and at correct height. Any tips for maintaining this during replacement are much appreciated.

 

[Jobsworth]

You managed to get it back where it was then? In you first post you mentioned they had gone way too high.
If they are right now you could chalk the upper edge of the beam on the garage wall and adjust them back afterwards

 

[MrGreedy]

You managed to get it back where it was then? In you first post you mentioned they had gone way too high.
If they are right now you could chalk the upper edge of the beam on the garage wall and adjust them back afterwards

Thanks @Jobsworth

So, the original head light level issue was that the arm can be connected in two different positions. When I removed part of the sensor investigating the cracked arm I was informed about at last service, I clipped the arm back in the incorrect position. Stupid. I should have taken a photo.

The current reading for both front and rear level sensors is -7mm in iCarsoft, but it passes MOT fine and lights work fine.

My current thinking is when I put the new sensor on, it will read something else.
Are you saying, regardless of what it reads, adjust the height screw (I assume there is one) on the front of both xenons so that for the reported flat ride height, the beam matches up with current position and it all sorts itself out from that baseline?

(for those wondering, I can't find a headlight adjust level option in iCarsoft).

 

[Jobsworth]

Thanks @Jobsworth

So, the original head light level issue was that the arm can be connected in two different positions. When I removed part of the sensor investigating the cracked arm I was informed about at last service, I clipped the arm back in the incorrect position. Stupid. I should have taken a photo.

The current reading for both front and rear level sensors is -7mm in iCarsoft, but it passes MOT fine and lights work fine.

My current thinking is when I put the new sensor on, it will read something else.
Are you saying, regardless of what it reads, adjust the height screw (I assume there is one) on the front of both xenons so that for the reported flat ride height, the beam matches up with current position and it all sorts itself out from that baseline?

(for those wondering, I can't find a headlight adjust level option in iCarsoft).

Yes

 

[Drpaul10]

Thanks Jobsworth. It was MOT'd yesterday and the tester manually adjusted both headlights to correct level. Now all working perfectly, which is great. Passed with zero issues and he noted what a nice clean example it was.

 

[john493]

I've had the level sensor link break on my 2011 C350, yes corrosion of the ball-pivots likely caused it. I just replaced the plastic link with a drum brake spring, adjusted to the same length (60mm) between centres. Seems to work fine. The sensor, if needed, is available from Autodoc at sensible prices.
My pivot plate was seized into the suspension arm, I just levered it out with a pry-bar. Febi 100090 is an aftermarket equivalent, although this does not come with the link-arm.

 

[MrGreedy]

So I replaced the headlight level sensor today with the new (revised) unit from Merc.

Two things to note:

1. The new sensor comes with revised linkages where the ball joints are capped/protected by a rubber boot and cap (circled orange), and therefore keep crud away from the ball joint that was previously open and caused the corrosion and resulting failure of all these original sensors. Also when moving the ball joint around, you can see grease squidging around inside through the cap which is a transparent, soft plastic.



2. From my original post and question No. 3, I couldn't get the metal plate off the suspension arms. This time I tried more penetrating fluid and heat, which I'm not sure did much if anything. The trick in the end was jamming a big, robust screwdriver into the underside of the plate in a gap next to the suspension arm (poked into where the green arrow is pointing), and being a bit brutal and prising the plate hard towards the front of the car and bending it away from the suspension arm. This then gave a reasonable amount of 'wiggle' to free off the corrosion binding the long threaded stud passing through the fixing hole in the suspension arm, and then it easily pulled out. On fitting the new sensor/plate, it was a loose push fit into the holes in the suspension arm, which just goes to show how much volume the aluminium corrosion oxide takes up, almost jamming the plate in situ. Hopefully these insights might help someone in the future if they fancy tackling this job.

 

[MarkNovack]

If you have succeeded in removing the plate from the control arm and its corroded that badly, just cut off the corroded threaded and positioning pins and drill for a 3mm bolt and captive nut. Or replace the entire unit with a Metzger. My Merc dealer recommended the Metzger because a stocking problem. I need left and right sensors (wagon/estate), however the original are still in good shape because they give them a shot of lubricant every year. I am putting on Hardrace adjustable camber arms but keeping a set of new OEM arms on hand with the original leveling sensors cleaned up. It has 175K miles but it looks and drives like it's just broken in.