W124 1995 E300D comments on recent ignition tumbler assembly replacement

[Texasgeezer]

I had searched & read several how to's before attempting to replace my failing ignition tumbler assembly. Still made a couple of mistakes that caused more time than necessary.

Ok things I did:
Removed old tumbler assembly as soon as possible after 1st failure to turn easily.
Ordered new tumbler assembly from Mercedes dealer, included new master key. Dealer had me show ID that matched my title info & sign filled out form. Learned this was done to reduce theft & shipment to foreign buyers.
Fashioned two removal tools from 12 gauge copper wire ( close to 2mm - no problem being soft & flexible ) Ends beveled about 45 degrees by wire cutters. Sharp point of beveled edge must be placed in the slot away from the tumbler assembly. This allows the two wires to push the three catches towards the center ( released positions ).
Set parking brake & set steering wheel to allow easier access to lock & to take load off of lock assembly.

Should have:
(1). Removed trim to expose lock assembly first. When I pulled out my failing tumbler assembly the protective black cover came with it. I pulled all that through the trim opening & caused the flexible rubber piece to separate from the trim. This took about two hours to figure out how to put the trim back together ( forced off plastic ring from trim, fit rubber piece, glued edge with epoxy gel, fit ring, weighted down with heavy socket til dry).

(2) Not done a test fit of black protective housing before installing new tumbler assembly. Took me a while to figure out there were two catches to release it. That makes three catches that must be released . One on the tumbler assembly upper side towards the rear ( 2 o'clock position ). Two on the main assembly about the 1:30 & 7:30 o'clock positions on the inside of the main assembly. These two are behind the tumbler assembly.

The upper wire tool first presses the tumbler catch down and then continues on to release the upper protective housing catch. The lower wire tool is used to release the lower protective housing catch. All three catches must be released to remove the tumbler assembly & the black protective cover.

(3) Made sure transmission was in park after installing new tumbler assembly. I couldn't remove the key & thought I had installed the new tumbler assembly wrong. Key removed easily after placing in park.

Comments:

If you use a screwdriver to turn the ignition switch after you remove the tumbler assembly - remember to turn the ignition switch back to the 1 position or the new tumbler assembly won't install properly.

It appears that both the tumbler assembly & the protective cover must be installed with the key in place & turned so the two wires can be pushed all the way back to release all three catches again. Tried to install without the wires but couldn't push all the way back to allow proper positioning. After inserting wires the two pieces easily went further back.

It appears both rear catches must be 'snapped' in place before key turns easily. My key would turn, but with difficulty until I fiddled with the black cover & heard a 'snap'. I guess that was one of the rear catches that wasn't seated properly. After that key turned easily.

1st image shows upper wire holding down tumbler catch spring approximate further distance to release upper catch for protective housing.
2nd image shows rear of tumbler assembly with black spring catch
3rd shows where two catches are that hold or release the protective housing. Also, some of the factory grease shows just above the bottom wire. It was still 'new' looking with no sign of drying out. Due to this I will be picking up some of the Mercedes lock lube.
4th shows the groove in the protective housing that the catches fit into
5th show the three pieces resulting from my error of not removing the trim piece first. I had to snap the small plastic ring off the trim, position the rubber piece, epoxy gel, install ring, weight down til glue dried.

[Dmitry at Pelican Parts]

Hello and welcome to the forum! I'm attaching a link to our site's DIY tech articles on the W124 platform. I hope you find these guides helpful when doing any maintenance or repairs in the future. Please let us know if you have any questions!

Mercedes-Benz E-Class W124 (1987-1995) Technical Articles - 300TE 24, 300CE 24, 300E 24, 300CE, 280E, 300E2.8, E280, 320TE, E320 - Pelican Parts