Many R107s come with one worn key, sometimes two, and often a key that only works if you jiggle it. Getting good keys is cheap insurance against being stranded.
Key types
R107s generally use a mechanical key system. Depending on year and market, a car may have:
- A master key that operates the ignition, the doors, the trunk and the glovebox.
- A valet or second key on some cars that operates only the ignition and doors, so the trunk and glovebox can be locked.
- On some cars, separate keys for particular locks after parts were replaced.
There is no transponder or immobilizer chip in R107 keys from the factory, so a correctly cut mechanical key will start the car.
Cutting by code
The best way to get a new key is to have it cut by code, not copied from a worn key. A key copied from a worn key copies the wear. The key code may be on a tag that came with the keys, on a lock cylinder, or obtainable through a Mercedes dealer with proof of ownership. Some locksmiths and specialists can decode a lock cylinder to find the code.
Worn key or worn lock?
- If a new key cut by code works smoothly, the old key was worn.
- If a new key is also rough, the lock cylinder tumblers are worn.
- If only one lock is a problem, that cylinder needs attention.
Lock cylinders
Lock cylinders for the ignition, doors and trunk wear. Specialists can rebuild cylinders and recode them to your key, so one key still works everywhere. A new cylinder from Mercedes may come with new keys, which means carrying two keys unless all cylinders are changed or recoded. See ignition switch and lock and door handle and lock problems.
Spare key
Always have at least two good keys. Keep one spare at home, not in the car. If you only have one key, get a spare cut by code as soon as possible.
Cost
A key cut by code costs relatively little from a locksmith or dealer, though original Mercedes blanks cost more than generic ones. Lock cylinder rebuilding costs more. Use quality key blanks; soft generic blanks wear quickly and can break in the lock.
Quick answers
- Can any locksmith cut an R107 key? Many can, if they have the right blank and code.
- Does the key have a chip? Not from the factory.
- Why does my key only work in one door? That cylinder is worn or was replaced.
- Can I get keys without the code? Yes, by decoding a lock cylinder.
