420SEL Instrument cluster removal
 

I pushed the mileage reset while I was driving. Both odometer and trip odometer quit working. Was told to remove the cluster and push the gears back together. Anyone give a DYIer and idea how to do that? Thanks, Ken

That happened to me once before. Push the mileage reset all the way in a few times and see if that fixes it. That's what I did and it started working again. Mine was working perfectly before I took it apart. That's when I started having problems. I'm going to replace mine as soon as I can figure out which model years will fit my car.

You can also take a look here. Maybe this will help get you started:

http://instrument.articles.mbz.org/renew/

http://www.peachparts.com/shopforum/tech-help/32102-how-remove-instrument-cluster.html?highlight=cluster

http://www.peachparts.com/shopforum/tech-help/71691-lets-pull-instrument-cluster.html?highlight=instrument+cluster+removal

Instrument cluster removed.
 

Thanks for the awesome help. Pulling the cluster was a breeze. The illustrayions were great.

Next problem: A little tiny plastic gear that drives the odometer is broken. There are three gears and it is the smallest. The easiest thing would be to replace the speedo section of the cluster. Where can I get a used one? Mine has 178000 miles. Also a outside temp guage would be nice. Ideas? TIA

My "tiny plastic gear that drives the odometer" is broken also.

You may get a decent instument cluster for cheap here. Just keep checking:
http://search.ebay.com/mercedes-cluster_W0QQsokeywordredirectZ1QQfromZR8

Just my luck, my odometer quit last night. Was turning 220,000 miles and guess it was too many wheels to turn. What really hurts, is that I just had cluster out to repair the clock. Now I'll have to pull it again and see if it busted a gear or the gear is just slipping. Someone mentioned a source for those gears once before I think. I can get a used cluster or speedometer from a local salvage yard, but I'd rather get this guy going.

My mechanic mentioned to me previously that there are speedometer shops where that's all they do - fix gears and such. I know there is such a shop in Dallas area, but I don't know where you live.

Having said that, be careful if you have to ship the unit for repair. Try to pack the unit with TLC. The unit is delicate and capable of breaking more with unecessary movements - like shipping.