There are two spring loaded "clips" just like you see in the picture above, that "lock" the black cap to the steering lock assembly. If you are not careful one or both of the clips can "fall out." A customer recently sent this picture asking what was the "left over part?" If you only dislodge one of the clips the other will hold the black cap in place (granted with a little less security). So don't worry too much if you find one of these clips on the floor of your Benz after installing the replacement tumbler.
Kent has designed some tools and filmed a number of videos to help you with your key and steering lock problems. REMEMBER, if your key starts to stick and you find it hard to turn REPLACE the tumbler right away or you WILL get stranded - and the repair is much more expensive if you can not turn your key. Kent even designed a special emergency release wire tool that will help get those stubborn tumblers out of the steering locks (provided you can still turn your key!). See related products below: