W126 exterior door lock

[Catman]

For many years I have gained access to my left-hand drive 300SE by unlocking the passenger door, leaning across to the interior handle of the opposite door and opening the drivers door. This weird performance is due to the fact that the key will not turn in the door lock cylinder on the door handle on the drivers door. It did work at one time, as my local Merc man put copious amounts of WD40 into the offending cylinder and the lock worked perfectly for about one week. Alas, repeat applications of WD40 will not make it work again. The easiest solution is to swap the front door handles so that I can operate the drivers door normally, and lock the passenger door via the central locking system. However, although I am able to easily remove the passenger door handle I am unable to remove the driver door handle as the key will not turn in the lock cylinder thus enabling me to do this. So my question is - how can I remove the exterior door handle now, and if there is a way of doing this - what is required?

 

[coalville126]

If you have a spare key, try it. I have had a similar problem in the past and a combination of worn barrel and worn key caused it.

 

[219]

I fear you may have to cut the shaft linking the lock barrel to the lock mechanism ; or drill out the tumblers .

I did the latter with my 280SE since the drivers lock would not turn ; I then swapped over the handle from the passenger side and fitted a spare handle from a scrap car into the passenger door .

I now have the beginnings of the same trouble on my 500 since it will lock but not unlock . I have a new spare key which made no difference .

A new handle ( the barrel is part of the handle ) , which comes with a new key , is around £120 , as I discovered when I asked at the dealer .

I still have another spare handle ( with key ) which I got from the same scrap car - so may do the same temporary fix as before , and have a look at the barrel when I have it out of the car ( I've repaired locks years ago , but they were simpler ones from a Ponton ) .

 

[Catman]

I do have a spare key coalville, but the results are exactly the same - unfortunately. Thanks for the suggestion anyway.

 

[Catman]

Your suggestion about drilling out the tumblers seems to be the way to go Pontoneer, but how would I best go about this? I can get a another handle from ebay, although it does not have a key with it - I suppose that one could go on the passenger door and the passenger door handle could then go on the drivers door - which I could then open with a key. Would I be correct in assuming that the handles (with locks) can simply be swapped from passenger door to drivers door? Thank you for your advice.

 

[219]

Yes , the handles can be swapped from one side to the other .

You need to be able to turn the key 90 deg in order to remove the handle , same to fit it , since the link shaft only goes into or comes out of the inner lock mechanism when turned .

Because the lock on my 280 was jammed when I bought the car as a project , I just drilled the barrel out ( after trying various penetrant and lube sprays to no avail ) . Just a matter of using HSS drills and working up to circa 10mm size until the barrel disintegrates - then you can remove the handle and get the shaft out on its own afterwards . The handle is destroyed , but no other part of the car damaged in the process .

 

[ianrandom]

Have you tried proper MB grease in there? WD40 freed it up by the sounds of it, but its also a solvent.
Mine has done this a couple of times and its always come back. Now I grease it regularly enough for it not to happen. Also, fitted remote locking so now that I think about it, wouldnt be an issue.

Why not consider that? Very easy if you get the right kit, I just tapped into two or three wires to the central lock pump in the boot. Voila, remote locking and no key needed.

 

[coalville126]

+ 1 on the MB grease.

Also did exactly that on mine. I also used a remote locking kit (from ebay) which tapped into the central locking pump. Took me less than 10 minutes after figuring out the wiring. No other physical modification / actuator required in the drivers door like on older RCL systems. Very discreet right down to the remote fob which came with a blank flick key blade. Works a treat. Done the same on my '80s VWs in the past.

 

[Catman]

I orderedthe mb lock grease today. I am interested in the remote locking kit, but there are so many on ebay that I cannot be sure which is compatible with a 1988 300SE - which one did you use and from where? Is it also correct that if I had this remote locking installed I would not have to worry about the drivers door lock not working?

 

[ianrandom]

Look for one that specifically says its compatible with MB pneumatic locking. There will be loads.
the one I used was Waeco, which is a good German make. Got it for £9, a bargain. 20 mins to install, after some considerable head scratching..

And yup, you wont need to use your key in the door after that so it will likely be cheaper than getting that lock replaced. Plus, much better, I hated having to use a key on a car like this.

 

[ianrandom]

Heres an example _ you'd need to ask the seller specifically if it fit MB pneumatic locking though. It says universal but hmmm. Anyway just to give you an idea.

 

[coalville126]

Yes, you wouldn't need to bother with your driver's door lock. I got mine from eBay.de a few years ago now and was about £40. Feels as like a quality OEM remote with flick key blade and still working fine.

If you search "W126 funkfernbedienung" on ebay and change your search location to worldwide, you'll get quite a few results. Choose ones without lock actuators as those will not have an output to the central locking pump.