How to fix door lock cylinder door on W124
 

Some years ago, the little "door" which keeps debris out of the door lock cylinder, when you insert the key, broke off. The then-owner didn't fix it because of the expense. Is it possible to get the part from a junkyard cylinder and transplant it? Or do I need the entire, rather pricey, lock assembly?

Anyone?

Sounds like that is probably part of the assembly. Don't be surprised if it's not big money at the dealer.

lock cylinder
 

One problem I will flag is that I have never seen any car in the junkyard that has a key.

So, if you bought lock cylinder from junkyard you would need to have ability to re-key - especially if you wanted to match your current keys.

Dealer can sell you one that will be keyed per your VIN and will not have the wear a junkyard lock would have on it.

I have bought new ignition lock & key for @ $100 and new trunk lock assy (& key) for @ $200 from dealer and they have worked out fine, but have had door lock apart to install new microswitch.

There have also been some threads here on switching passenger side door lock to diver side, but I do not recall if it turned out to be do-able at the end of the day.