I thought I would do a quick DIY for this as I found all the internet examples a little confusing. The W209 chassis is quite different to the W203 and W211. You can replace the broken spring in the door lock actuator without removing the lock. I personally would recommend this method as the alternative is to move the window regulator out of the way which also requires you to completely remove the window from the car. This is not that difficult but aligning the window back in will very painful.

This is a very fidly job but it definetly can be done in 1-3 hours depending on your fiddling ability :P If it's your first time, definitely give yourself 3+ hours.

I haven't put the removal of the door card in here or the lock itself, there are threads all over the place about how to do this. However I did find (on the passenger side anyway. That there actually is not need to remove the outside door handle contrary to what WIS says.

Here is some quick notes on the job and then some pictures of the install. Including what it looks like if you do it wrong.

1. Remove door card.
2. Remove bottom speaker.
3. Remove the 3 screws holding in the lock to the door.
4. Wriggle it's *** down to the speaker whole.
5. Take the screw of the door lock actuator off.
6. Remove the cover (very fiddly doing this with the lock in the car, but more than doable. Take your time. There are I think about 4-5 clips holding it in. If you brake any clips don't worry too much about it as long as you have 2 left the screw will keep the cover firmly in place.
7. Remove the old spring if it hasn't disappeared. If it isn't there there will still be one metal piece stuck in the bottom hole. ( You will see what I mean by bottom hole when I put the picks up).
8. Put the new spring in. Be careful if you have multiple new springs they are not all the same, The RHD and LHD of the car have different springs. If you find your old spring it will be easier to pick the right spring. Don't worry to much if you get it wrong you will notice that it doesn't look right when you try to put in based on my pictures.
9. Push the lock up and down manually you need to feel a slight lock both up and down when pushing it. Mine made no metalic clicky sounds as others have reported with w203 locks. You may need to remove the lower black gear to do this, don't worry if you don't know what this is, it will most likely fall our anyways when you messing with the lock and you will figure out how to put it back in, it's very simple when it actually happens to you.
10. Lubricate the crap out of everywhere. I just got some lithium grease and sprayed it over everything.
11. Put the cover back on.
12. Slide the lock back up. This can be a little painful, there is a plastic cover at the top that is in the way and caused me some headaches. It covers the lock but the metal handle on the lock (You will see it when you get there) Actually has to go behind the cover, but the rest of the lock is at the front of the cover.

 

Nice write up!

 

Hope it helps someone out As painful as this is. This is a $5-$10 fix. Well worth the pain

 

A heckuva lot better than $100 for a new lock - not counting labor!

 

I think the cheapest I found was $112. Which is pretty reasonable. In Australia I'm sure it close to $400. The problem with the new lock though is that you have to get it out of the whole. I think stealers will be charging easily 3-6 hours labor.

 

I followed the procedure, but something odd happened.
The bouncing only stops when the door is open, even when I press the contact to simulate a closed door.
Once the door is really closed, the bouncing returns.
I wonder if the latch position has something to do with this.