E Class (W211) Parking sensor removal - How I did it.

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Turbo Merc

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My parking sensors packed up when I was out driving in the pooring rain for a couple of hours. I reasoned that if they started to work again after the car had been in the dry for a couple of days, water must have got in somewhere and shorted something out. Sure enough, once the car was thoroughly dry they worked perfectly again. Given that the front sensors get the worst of the rain, I decided to take them off and seal them with a waterproof sealant to see if that stops it happening again.

Having received a copy of the MB workshop instructions for the removal of the bumper strips and the front parking sensors, I thought it was going to be a simple job; just a case of following the instructions after all! I could not have been more wrong. The photographs had been taken so far away from the bumper that there was no detail visible and the instructions: 'Unclip protective molding (1) at latching hooks (arrows) from front bumper (2) with long wedge' were completely useless. I was tempted to give up, as MB probably planned, but I was determined to do the job using my age old adage "someone put it together, so I should be able to take it apart' - the caveat is of course that I may break something trying, but that does not put me off too often!

Here is the standard health and safety/libel/damage cop-out and warning - if you follow what I did you do so at your own risk. This bit is a personal, genuine warning, based on my experience - be very very careful what you do! The job does not require a degree in rocket science but I nearly scratched the wing on a couple of occassions when I slipped so you have been warned. If you are not competent then get a specialist to do the job for you.

If you intend to follow what I did and have a go yourself (AT YOUR OWN RISK) it would be worth reading ALL of this posting and looking at the photos first because I will tell the story as it happened rather than as an expert's guide - I am not an expert and I would not attempt to tell anyone what to do! So this is my experience of how I removed the bumper strip and the parking sensors:

The MB manual states that you should protect the paintwork with adhesive tape - very sensible and if you have tons of tape it is worth doing; I didn't. Because I am a bloke and I don't follow instructions that well (instructions are for wimps lol) I chose the 'I will just be careful' route. The manual also says to use a flat plastic wedge to unclip the clips - I could not find anything strong enough so ended up using a flat bladed screwdriver ( a stubby one so I had more control) wrapped in cloth. This is a really risky thing to do owing to the risk of slipping and scratching the car but I had no other option. I managed to very slightly lever up the bottom outer edge of the bumper strip and slide the srewdriver in between the bumper strip and the bumper itself. I did slip a couple of times trying this but was lucky SO BE VERY CAREFUL if you try this yourself! I had no idea where the securing clips were, or how to get them off, so I just had to chance it by sliding the screwdriver along until I met resistance and, assuming that I had found a clip, lever away until I either undid something or broke something! The bumper is of course made of plastic so when I twisted the screwdriver a bit too far I did make a ver minor dent in it but as it was on the bottom edge it is not visible - I learnt my lesson!

Thankfully I guessed how to do it right and the bumper strip popped out a bit. Using the rationale that there must be a similar top clip I tried to repeat the process on the top edge. However, that was not possible because by pulling the bottom edge out I had really closed up any gap on the top edge and this meant that if I tried to force it I was in real danger of slipping and scratching the panel. My next action was to try to find the next clip on the lower edge. Making sure I did not let the first clip click back in - I used a wooden peg to keep the gap - I slid the screw driver along until I found the next clip and repeated the process. Thankfully it worked well.

After undoing two clips I could pull the bumper strip out far enough to see how the clips actually worked. As they were in essence fairly strong, but simple, plastic hooks that were an integral part of the bumper strip I gave the bumper strip a bit of a pull downwards and outwards until I started to undo the top clips that were nearby. I continued levering, pulling and wiggling confident that the whole strip would now just unclip all the way along. WRONG! Some clown at dear old MB had decided it would be a great wheeze if they changed the type of fastener half way along the strip! As a result I nearly broke off the middle parking sensor mounting piece on the rear of the bumper strip! The clips by the sensor were a pig and would not undo for some reason. After too much force was applied and I nearly broke off the senor mounting bracket, I managed to see that the clip was different!! Thankfully I was being as careful as possible given that I had no idea what I was doing, and as such managed to stop in time before complete disaster hit.

The second type of clip used is a sliding hook arrangement, it works by sliding the bumper strip outwards to remove it and sliding it inwards to install it. Having worked out the sliding process I pull the strip firmly towards the side of the car and it slowly slid out. Again, I had to be careful as the sensor wires are not very long and it would have been easy to pull too hard on them. The bumper strip was now hanging by the sensor wires.

Once you have removed the bumper strip, removal of the sensors is dead easy and anyone will work it out with a simple glance. I removed each sensor in turn, cleaned them up, and made sure the connectors were tight. Once clean I completely smoothered the rear of the sensor in a clear, silicone waterproof sealant. The sealant came from Wickes and it was recommended for exterior sealing of joints in houses, windows etc so hopefully it should be fine for the sensors! I then cleaned the sensor housing in the bumper strip, and applied a copious amount of the sealant to the front leading edges of the sensor (when you remove it you will see that the front of a sensor is like a flat top mushroom). The aim of this was that when I pushed the sensor back into the bumper strip housing it would create a watertight seal all around the front of the sensor. Once the sensor was back in place and properly clicked in, I wiped any excess sealant off the front of the sensor and bumper. I then repeated this process for each of the sensors.

Replacing the bumper strip was a doddle but two things to look out for: Firstly, when you remove and replace the sensors in the bumper strip make sure you replace them the correct way around - wires to left or right as they were when you removed them. Secondly make sure you tuck the sensor wires back into the bumper openings otherwise they will trap between the bumper strip and the bumper when you refit the bumper strip.

Having tucked the wires away I engaged all the sliding clips back in the bumper and slid the bumper strip in towards the centre of the car. I had to do a bit of sidewards slapping movement to make it move as it was a tight fit. Once the bumper strip had slid in fully I just gently banged home the other clips. Once again, I checked there was no excess sealant on the front of the sensors and tested that they are working alright. It might be worth testing they all work before removing them just incase you have a duff one before you start!

Having worked out how to do one side the other side was a piece of cake and took no time at all to complete. Job done!

As I stressed right at the beginning, no matter what you decide to use to lever the bumper strip off do be very very careful, it is so very easy to slip and put a huge scratch along your pride and joy :-(

I will let you know if I have been successful after the next time I go out in an absolute deluge.

Safe tinkering!

This forum is too small to post all the pics so I have put them onFlickr: This is the link: http://www.flickr.com/x/t/0092009/photos/64450505@N03/sets/72157626913669189/ hopefully it works!

Pic 1: Close up of the clip type fasteners. This will help you to understand how they can be removed/refitted.
Pic 2. Outside edge removed
Pic 3: Inner section removed.
Pic 4: Close up to show the location of the outer edge clips.
Pic 5: Close up to show location of the top clips near the frist (outer) sensor - Bottom edge clips are virtually in mirror locations.
Pic 6: Close up to show the damage I did to the centre sensor mounting - note it is a sliding fit, and the sensor mounting unit fits into it (grey square lugs).
Pic 7: Close up to show sliding clips between middle and inner sensors.
Pic 8: Close up to show sliding clip on inner end of bumper strip (nearest to radiator)
Pic 9: Complete bumper strip hanging by sensor wires.
Pic 10 & 11: Close ups of the sensor in the sensor mounting unit.
Pic 12: Inside of the sensor mounting unit after the sensor has been removed - clean this out before replacing the sensors.
Pic 13 & 14: Close ups of the sensor smoothered in sealant before being pressed back in to the sensor mounting unit.
Pic 15: Pic showing how I used a screwdriver to prise out the lower edge of the bumper mounting strip - Final warning: use extreme caution to avoid slipping and scratching your car!
Pic 16 & 17: How I pulled the bumper mounting strip once I had undone the first few clips.
 
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