How to adjust and/or reinstall the roll bar sensors - Mercedes-Benz Forum

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Old 02-15-2005, 12:57 PM   #1 (permalink)
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Date registered: Jan 2004
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re: My first experience with a 2002 roll bar reset after deployment

If the roll bar pops-up, you should press the switch as if trying to raise the bar for several seconds until you hear a "click". This re-engages the drive mechanism so that you can then lower it with the switch normally.
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Old 04-11-2005, 07:34 PM   #2 (permalink)
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How to adjust and/or reinstall the roll bar sensors


I installed new shocks and struts yesterday. That went very well. The problem that I am seeing has to do with going aound turns with a slight lean, all of a sudden, the roll bar pops up. Once the roll bar has popped up, when I go around a similar turn, the central locking system disengages all locks except for the drivers side. If I had the roll bar back down, it would pop again

Does anyone know what could be causing this? It was not happening before the shock/strut install. But is it possible that they are settling or....? Not real sure.

Thanks in advance
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Old 04-13-2005, 02:21 AM   #3 (permalink)
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re: 1990 500SL Installed shocks & struts..Roll bar pops up now????

New components naturally can affect how the suspension sits. Sasor, you probably need to adjust the position of the rear axle limit switch assemblies shown in the attached photo.

Each switch assembly has a mode selection switch on it with a position for normal operation ("funktion") and another for testing ("arretiert"). To adjust a switch, first jack-up the rear of the car so that the associated control arm is fully extended and tire is off the ground. Turn the mode selector to arretiert. Now loosen the switch assembly mounting bolt and position it so the tip of the switch just barely comes into contact with the covering on the control arm. Tighten the mounting bolt, return the mode selector to funktion, and lower the car.
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Old 04-13-2005, 05:57 AM   #4 (permalink)
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re: 1990 500SL Installed shocks & struts..Roll bar pops up now????

bobterry99 is correct, but I think this should be done at the MB dealer, because this is a safety issue. If you get it wrong, the rollbar is´t poping up and you are going to get a headache (in best case).
No supercharge, no turbo. Just real power. Luke says -A obsidian black SL60 ///AMG and S600L from -96. That´s his cars, and the force is with him!
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Old 04-13-2005, 02:30 PM   #5 (permalink)
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re: 1990 500SL Installed shocks & struts..Roll bar pops up now????

I don't know if I agree with the tone of the above post, but I strongly agree that Sasor should perform the adjustment himself. The axle switch adjustment really is simple and impossible to get wrong, I believe. My opinion is moot, however, because there is a test to verify the adjustment.

To check an axle switch, put its mode selector in the arretiert position. Drive the car to a speed of at least 6 MPH and apply the brakes fairly hard for a short stop. The roll bar should deploy. Lower the roll bar, return the mode switch to the funktion position, and repeat the preceding test for the other axle switch.
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Old 02-11-2007, 03:31 PM   #6 (permalink)
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I just adjusted a switch on my car, just follow the instructions from Bob Terry, you can't go wrong
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Old 12-30-2007, 02:20 AM   #7 (permalink)
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How to adjust and/or reinstall the roll bar sensors

Hi guys,

The process is very simple, all what you have to do is follow the below steps for testing and replacing/adjusting the sensor:

- Testing the roll bar sensor:

Set rotating part (1) on one of the two rear axle switches to "arrested".

Then drive the vehicle to test. The roll-over bar should extend (crash actuation) when the vehicle is braked sharply from a speed of approx. 5-10 km/h . After testing set the rotating part (1) back to "Function".

NOTE: A clicking noise is audible as the roll-over bar extends.

- Replacing the roll bar sensor:


Roll-over bar
put up with convenience switch
switch off
Negative pole on battery
disconnect and cover
Connector for rear axle switch on left (S3/2x) and right (S83/3x)
release by pressing (arrow)
Nuts (2)
Rear axle switches (S83/2,S83/3)
Nuts (2)
retighten (4 + 0.5 Nm )


NOTE: The rear wheels must hang freely (rear axle suspension extended completely)

Rotating part (1) on both rear axle switches
turn to arrested position.
Nuts (2)
Rear axle switches on left and right
position on bolts. Tighten nuts (2) hand-tight.
Rear axle switches
grip with hand on lever and position tip (3) against covering (4).
Nuts (2)
tighten (4 + 0.5 Nm ).
Function of roll-over bar
Roll-over bar should actuate. (see the testing above)
Rotating part (1)
turn back to function position.

Hope the above information will help you to fix your problem.

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Last edited by ogn; 12-30-2007 at 02:58 AM.
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Old 12-30-2007, 04:53 PM   #8 (permalink)
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Old 06-18-2008, 04:25 PM   #9 (permalink)
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Date registered: Jun 2008
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Roll bar stuck and soft top won't open

We contacted dealer - service advisor who knew the exact problem. He told us it took a special tool to fix and would take an hour, only $150.00. Good deal huh? Well, after reading your 10 sec rule about holding the role bar switch in the up position, the mechanism clicked and it worked again. I know what the dealer's special tool looks like now, but I can't post a picture of it. Thank you
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Old 06-19-2008, 01:14 PM   #10 (permalink)
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Location: Raleigh, NC
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Roll Bar activation depends on two sensors near rear wheels underneath the car. In some cars they set way to sensetive and could be easily adjusted. It is simple DIY job of about 5 minutes. Details were published here some time ago.
I remember my Roll Bar was popping out way too often to my liking, so after small adjustment, I can have some fun without being scaring passenger. Of course, when I am having too much fun, it poops up as expected.
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