I changed the tumbler on my 1991 300CE, W124 and yours might be similar. I found a post that described making the tool to push into the two holes. Coat hanger wire worked perfectly. Use 300mm length of wire. Make two bends 20mm apart to form a "U". Grind the tips to a 70 degree, inside angle. Like making a large staple. The angle is important as you can see when the tool is applied to your new tumbler. Mine took a hard push on the tool and lots of jiggling. As other posts have warned, keep the key in position "1". Getting it stuck in any other position is not good.


Good Luck,


glenmore