560 SL Trunk Lock Problem - PeachParts Mercedes-Benz Forum

rbr54 · #1 05-13-2011, 09:36 PM

The trunk lock on my 1988 560SL is no longer operative. I've got a vacuum leak at the trunk lock actuator that I suspect is preventing the lock mechanism from dis-engaging. The fuel door was also stuck in the locked position and I was able to get it operating with my vacuum tool. Not so with the trunk lock.
I'd appreciate advise on getting in the trunk to make repairs. Neither the paper manual or CD version shows a release like you find on a sedan. Can the trunk lock be defeated? Is it time to drag out the old slide hammer?
Thanks

abiby · #2 05-13-2011, 11:16 PM

You can search for instructions for drilling a hole to access the latch, but IIRC if the issue is just with the vacuum central locking, the key should still open it.

RadioTek · #3 05-14-2011, 01:40 PM

Have you had trouble getting it open with the key?

There's sort of a 'procedure' to it on mine; You have to turn it all the way to the right, to sort of reset everything, then turn it as far to the left as it will go. It ends up at about 45 degrees past horizontal, but then I can push in the lock button, and pull up on the trunk lid. Sometimes it takes a bit of 'oomph' to get it open. I got this procedure from a post somewhere, so I can't give proper attribution, but it's worth a try before you have to do anything drastic.

Good Luck
Scott

rowdie · #4 05-14-2011, 02:19 PM

Do you have the master key? It has a square head and originally a red dot. Manual says using master key turn completely to the left and allow to return to vertical. Push button in to release latch.
The round head key is the valet key and will not unlock the trunk.

rbr54 · #5 05-16-2011, 09:51 AM

Thanks to all for your help and advice. I have been using the master key and following the procedure in the manual. The key does not return to center after I turn it and let go. I'm going to keep working it and will use a little more muscle pushing in and up as I try to open it. If anyone has advice on actually drilling and/or defeating the lock I'd appreciate it.

Jack M · #6 05-18-2011, 06:41 PM

HI, Before you take a hammer to the lock mechanism I would have in my hands both a new cylinder that is keyed to your ignition key and the lock mechanism that the cylinder mates to.

Some one had this issue last year and did drill the mechanism and not the cylinder. There is a measurement that will allow you to drill a hole and push in a steel rod to release the lock mechanism. If you have a friend with a 107, look to see how the mechanism works.

Have you tried various lubricants? Automotive cylinders are constructed with small wafers about the size of a dime and they do get out of alignment and get sticky. 20 years in the weather takes it's toll. It is not anything like a pin tumbler on a house door lock.

Relax and don't get desperate. Be patient, there is lots of help available here.Best of luck, J

Jack M · #7 05-18-2011, 06:58 PM

Hi Again. Go to" Search this forum" type in "trunk lock" As you scroll down there are several suggestions. Just do them one at a time. Really try to avoid the HAMMER. J

rocky raccoon · #8 05-18-2011, 09:12 PM

I too contemplated drilling. At the advice of others, I did not. Exercise patience and a lot of TEFLON-based lubricant. Not WD-40, not graphite and definitely no form of oil.

Drilling the lock out or using the slide hammer method will not open the lock. The mercedes lock mechanism is designed to withstand that.

Teflon is the only way to go. Ask any locksmith. Flush through the keyhole, insert key and wiggle. Flush some more, insert key and wiggle. Repeat until the miracle happens.

Good luck and let us know when you get in.

rbr54 · #9 05-24-2011, 10:07 PM

I';m working it via the lubricant route. No luck yet but I'll be patdient.

Jack M · #10 05-31-2011, 12:12 AM

Hi, Since we have not seen a "got it open" post I assume you are still working on it.

Did you key ever work in the lock? Or did you usually lock the trunk by locking it using the vacuum system and the door lock? J

rbr54 · #11 06-17-2011, 07:03 PM

Still working it w/the lubricant. It did work with the key untill recently. I've experienced the usual vacuum trouble in that end of the vehilce with the fuel door too. Used a vacum pump at the "T" in the glove box to get the fuel door open. The key doesn't return as it should when turned. This is a great car and my only problems have been the trunk lock vaccum and the A/C system. I'm working on that right now as well. Just want to get the defroster working for state inspection.

Thanks again for your advice and interest.

Jack M · #12 06-23-2011, 01:32 AM

OK, Since these keys are side cut blades not like top and bottom blade cuts I am going to take this set of replies to my friend who is a very experienced automobile locksmith. We will see if he has any suggestions. I have a 86 560 so he may have some suggestions. I also have access to key blanks for the SL maybe we can find a way to make a key that will open the trunk.
Look at your key is it damaged in any way? The full keyway is needed to start the car but not all of the key cuts are needed open the other locks.

The key you have opens all of the doors, glove box and ignition? Right

He may have the best tech info to do other things . Hang on for a few more days, Jack

Jack M · #13 06-23-2011, 07:59 PM

Hello again, Well since I have time on my hands I took my latch apart Hold the Phone!!!
There is a way, With no real damage. I will be back soon with the exact method exactly.

Do not proceed with anything else. Key slot needs to be vertical for this to work. measurement and procedure to follow soon. Jack

chaos23 · #14 01-31-2014, 03:38 AM

[B]HELLO JACK!!!

Will you please post the procedure because I've tried lubricating around and inside the lock, and tried pulling the button out, but nothing has worked. The button seems really stuck. I'm ready to drill through the button (but I don't know the part number for a new cylinder).

If there's another way to get the button to come out or release the locking mechanism, please let me know.

Thanks for any help you can provide!

nobby · #15 01-31-2014, 06:34 AM

Quote:

Originally Posted by chaos23

[B]HELLO JACK!!!

Will you please post the procedure because I've tried lubricating around and inside the lock, and tried pulling the button out, but nothing has worked. The button seems really stuck. I'm ready to drill through the button (but I don't know the part number for a new cylinder).

If there's another way to get the button to come out or release the locking mechanism, please let me know.

Thanks for any help you can provide!

Old thread, chaos.

What year is your car and what is the exact problem?