My 420SEL trunk lock is starting to act very peculiar. I don't know exactly how they are designed to work, but mine always locks when I use the key in a door. Using the key in the trunk will also lock it and all the doors when I turn the key to the right. Recently I noticed the trunk lock will no longer operate easily when I try to lock the car from the trunk lock (like when I get into the locked trunk for a piece of luggage and then re-lock the car using the trunk lock). It is now very hard to turn the lock to the right (turning it left is OK) with the key; it feels and sounds like there is something about to break off or fall off inside. It still unlocks fine when I turn the key to the left and the vacuum mechanism seems to work OK for all the various locks, trunk included. It just seems like it is about to fail whenever I try to lock or re-lock the trunk using the key in the trunk lock rather than at a door.

I first noticed this on our vacation where I was constantly getting into the trunk to remove or stow luggage. I stopped using the key to lock the trunk and only used the door locks after noticing this. Is there some bit of maintenance I should do or is there some common little plastic part that fails and needs replacement??

Any help you can offer will be appreciated.

Many thanks,

230/8

p.s.: The old girl ran like a top on our vacation...over 5,200 miles and not a single hiccup or miss...gave us 20+ mpg for the whole trip. Great cars.