More on door locks...and keys - PeachParts Mercedes-Benz Forum

miner · #1 07-03-2006, 02:24 AM

I had a drivers side door lock that was frozen. Using the articles in the DIY area I was able to get the cylinder out of the handle. Everything is fixed good as new, but I thought I would share a few things because it can keep you from having to go to a locksmith, or ordering a new door handle with key which is expensive (and if you get it matched to your current key it is VERY expensive). Basically, you should never have to do any of these things to get a perfectly working lock.

My car is an 84 300d.

Anyway, I when I got the cylinder out and started taking out the leaves I discovered that my trouble was a cylinder packed with grime. It actually looked like someone kept spraying graphite into it until it became packed. No amount of jiggling or using an electric sander was going to work. What I noticed when I started cleaning the leaves is that they are numbered, and that there are only 4 kinds, labled 1, 2, 3, and 4. Just write down the number of the leaves in their order and you wont have to worry about keeping them in order after that.

Also, if some leaves are damaged beyond repair you can do two things. 1) just leave that leaf out of the assembly or 2) go to a junkyard and get another lock assembly and scavenge the leaves. You can scavenge the cylinder too if yours is too corroded. All you have to do is put the new leaves into the right order with your old ones that are still good and you will have a perfect locking cylinder.

One other thing that I ran into: my key wouldnt go all the way into the cylinder at first. This is because there is a little slot at the end of the cylinder that the tip of the key goes into. If this gets plugged up (like mine) it is a real pain in the behind to get cleaned out.

You can even read off your unique locking number straight from your key. Basically there are ten leaves which correspond to ten places on your key which vary in height or thickness. The minimum thickness corresponds to leaves that are labled "4" progressing up to the maximum thickness corresponding to leaves labled "1".

One last thing. The leaves are made of brass -- or at least something that looks very much like brass. There's been a lot of posts here that I have read that say you should only use an official MB steel key. Now I don't know about the ignition cylinder, but I would expect it to be similar. And brass on brass sounds like it will lead to a lot less trouble than steel on brass. If you have a pure brass key (without the nickle plating) you shouldn't get any metal filings in your lock at all. With steel on brass, it might be a different story.

TwitchKitty · #2 07-03-2006, 06:09 AM

I recently went through this with the hatch lock on my subaru salted road beater. The lock is constructed just as you describe with the exception that it has eight leaves and I didn't see where anything was numbered.

At first my key wouldn't go in the lock but it was because the leaves were jammed in place with corrosion, etc. PbBlaster was recommended in some of my searches here for cleaning aluminum and so I gave it a try on cleaning the gunk out of my lock. It seemed to work pretty well.

I did as you mentioned and left out one leaf that seemed problematic.

miner · #3 07-03-2006, 11:38 AM

I used PB Blaster and Brake cleaner, but neither was very good at getting anything except grease. I scrubbed at the corrosion and really crusty stuff for like 2 hours until I gave up on chemicals and just used fine grit sand paper. That got things slick and shiny and went quick.

The numbers on the leaves, for the MB locks, are on one side right next to the little tabs that stick out. I didn't notice them until I really started to get the leaves clean.

TheDon · #4 07-03-2006, 12:01 PM

i tried some white lithium to free up my lock and it worked like a charm

TwitchKitty · #5 07-03-2006, 12:36 PM

I used a baggy and a small cup to soak the whole part with the leaves in the Pb Blaster. I soaked it for over an hour total. I took it out from time to time to try to work the leaves loose one at a time and blow it out with compressed air. I cleaned one leaf with a scrubbie pad but maybe didn't get it clean enough to see numbers if they were there.

I have tried to collect some books on locksmithing but they weren't cheap when I looked.

gmercoleza · #6 10-02-2006, 12:12 PM

Just went through this on the W126 380SE. For the last couple weeks, I have had to lock/unlock from the trunk (not too cool) due to a jammed driver door handle lock. Everything works great now, and this was a very fun, satisfying project. The rebuildable nature of these cars continues to amaze me - sort of like the 747 of the road!

Taking everything apart was simple enough. I used Gunk engine degreaser to clean everything. In my case the jammed lock was caused by impacted graphite and grime as well as a couple of leaves that were somewhat twisted and kept jamming up. I left those leaves out. A few tips to help the next guy who has to do this job:

* To make removal of the handle easier, unscrew all 4 door latch assembly mounting screws. This allows the latch to move about freely, giving enough slack to rotate the handle the required 90 degrees for removal.

* Remove the interior door release handle and the connecting rod to provide even more slack.

* A small baby food jar works wonders for soaking the components in degreaser or cleaner. Screw the lid on and shake all that grime and dirt away!

* BIG TIP: I spent an hour and a half trying to reinsert the shaft with inserted leaves into the sleeves. It was an exercise in frustration! After cleaning, the leaves were so clean that they would jump out of their slots if I looked at them wrong. Save some time and your neck by just inserting the key - Duh! Inserting the key keeps all the leaves in place and you can insert into the sleeves in about 5 seconds.

* If you lose one of the detent ball bearings, be sure to leave out the associated spring. Otherwise the spring will just jam up in the detent. If you lose both ball bearings I think you're in big trouble since you need at least one to accomplish the detent action.

* Be careful to note the position of the cylinder inside the sleeves. I accidentally rotated 180 degrees and had the worst time trying to figure out why the cylinder wouldn't rotate even after the defective leaves were left out.

riethoven · #7 10-02-2006, 12:24 PM

Quote:

Originally Posted by miner

I used PB Blaster and Brake cleaner, but neither was very good at getting anything except grease. I scrubbed at the corrosion and really crusty stuff for like 2 hours until I gave up on chemicals and just used fine grit sand paper. That got things slick and shiny and went quick.

The numbers on the leaves, for the MB locks, are on one side right next to the little tabs that stick out. I didn't notice them until I really started to get the leaves clean.

I have done too much rust removal from things like cast iron machine tables and many other parts. I have found that for flat surfaces and even round ones a single edge razor blade will actually scrape off the rust without distorting the surface like sandpaper or a stone can. Lube the surface up with just about any oil then use the razor blade to scrape the rust off. If it is really bad I will coat with Marvel Mystery and leave for a couple of days so it will soften up. Once I start scraping, I just use mineral spirits. Also, IMHO scraping takes less time than sandpaper if there is a buildup of rust on a part.

Thanks for the post. My wifes 1985TD hatch lock would not accept the key. I was amazed how much crud was in there. Gave it a good cleaning and lubed with marine grease and it works like a charm now.

dieseldiehard · #8 10-02-2006, 01:33 PM

This thread reminds me of what my brother, a locksmith, told me once, he said that graphite lock stuff is a locksmiths best friend, in that it jams up locks and eventually brings the owner to call a locksmith!

I learned this lesson years ago when I bought a can of the stuff and squirted it in my Saab locks. A year later they started acting up. I shot WD-40 in them with the key half way in the lock to open the path and flushed it out using the key to work it loose.
I recently had a 124 car with a lock that jammed in the cylinder, it was almost impossible to pull out, I shot some Hoppe's oil in it. Then some Teflon spray lube and it came out with some jiggling. Never figured out why it was jammed in like that. It was a new key, maybe that was a factor.

And miner, who says brass keys won't leave metal filings in your lock? Mine sure was full of it, about a year ago I removed the leaves from the cylinder on a 123 300TD I have owned since about 1991. It came with a aftermarket brass key and it finally wore down so much it would hardly work so I ordered a factory key. Its amazing how one can fix little things like this on these cars.

airbus · #9 10-02-2006, 01:54 PM

I just scared the crap out of myself. I fixed the trunk lock (working fine now) and OOOPS, my car has an alarm

.

gmercoleza · #10 10-02-2006, 01:57 PM

Yes, I forgot to mention the alarm. There is a sensor that wraps around the lock cylinder - magnetic, I'm guessing. From the sensor there is a wire that plugs into a connector, I'm guessing this is for the factory alarm system. When I removed the lock cylinder, I also removed the alarm sensor and didn't reinstall it afterwards since I have unplugged my factory alarm system. If you are reading this, you should be aware of any effects of improperly reinstalling this wiring and/or sensor.