R170 boot lock

[Jetl3on]

Hi,

Sorry if this has been covered but finally managed to get the key in the lock of my r170 after days of fiddling with the key and WD40, but it won't turn, so a bit more messing about I presume? does it lock via remote and central locking or manually using the key?

Thanks

Jet

 

[Dec]

What year is the car?
See… Mercedes-Benz SLK 230 Trunk Lock Cylinder Repair | 1998-2004 | Pelican Parts DIY Maintenance Article

When the key is fully inserted into the lock… compare how far in it will go in the door lock or glove box lock… it should turn, if it doesent then it is still partly seized.

Flood it again with WD40 , have the boot lid open when you squirt the oil in so that gravity brings the oil down into all of the lock mechanism, leave the boot open for a while and repeat as often as possible.

Dec

 

[Jetl3on]

Good idea, will try comparing depth.

Its a 2000. I was thinking maybe the outer shell of the chrome lock barrel was also seized against the plastic holder and wont turn maybe?

Thx

 

[Dec]

If the key blade goes in fully then its further back in the lock that is seized.
The key can/will turn to the left or right when freed up, I think you may also need to operate a handle or push the lock inwards in order to open the boot lid.

Dec

 

[Jetl3on]

This one has a handle, so the lock itself is fixed, just a matter of left/right I need to get going. Thanks.

 

[Dec]

The boot should UNLOCK when the car is unlocked with the remote or cabin locking switch, either the mechanical link between the handle and lock has failed or part of the vacuum pump or tube/actuator has failed.

The best thing to do would be to remove the lock (mark its screws location to aid replacement) as far as in the picture below.

Leave the pneumatic line (Yellow arrow) detached and with the boot open, operate the remote to lock or unlock, you can do this while the boot lid is open, you may need to switch off the boot light at its switch, if it has a switch.

When you unlock the car, air is blown thru the Yellow tube, yes?
When you lock the car, air is sucked thru the Yellow tube, yes?


The car alarm won't go off while the boot lid is open… but, if it does then unlock again with the remote to disarm it.

Aside from the seized lock, this might be a problem with the vacuum pump and explain why the fuel flap is also faulty.

Dec

 

[Jetl3on]

Good detailed plan, thanks. This pneumatic pump, it's possible for part of it to fail and not all of it? Where will I find it and what else does it feed, boot lock, fuel flap, roof??

Sorry for all the questions.

Jet

 

[Ted]

Take out the spare wheel and the jack and you will see it wrapped in foamy stuff.
It is easy to remove and disconnect - just mark the vac pipes.
They are well known for getting water in, but are easy to dismantle and dry out.

 

[Dec]

Have a quick look for signs of water damage to the pump, however its best to investigate the boot lock and the petrol flap for faults first before taking the vacuum pump apart. Try the test in my previous post to see if the Yellow vacuum pipe is sucking and blowing when locking, you could also remove the fuel flap Yellow pipe too, to test if it is sucking and blowing air when you lock/unlock.


Needs translated to English… Berliner SLK Stammtisch | www.BeStSLK.de - Trockenlegen der Pneumatischen Steuereinheit (PSE) Incl. Aus- und Einbau

Long thread here… PSE - Removal, Refit and Check - Mercedes-Benz Forum

Dec

Edit, I see in the diagram above, which is of a left hand drive car, the passenger door and boot lock share the one outlet from pump, 15 & 16 in diagram.

Try pressing the remote fob unlock button twice to see if that has any effect on the boot lock opening. Is your remote fob a flip out key blade type?

 

[Jetl3on]

I can't tell from your picture, but removing lock must be straightforward job.

Thank you both for the pointers, will give it a try.

Jet

 

[Dec]

There is an American guide with pictures here... Mercedes-Benz SLK 230 Trunk Lock Cylinder Repair | 1998-2004 | Pelican Parts DIY Maintenance Article

Mark the lock screws with a marker to aid putting it back together.

 

[Jetl3on]

Have a quick look for signs of water damage to the pump, however its best to investigate the boot lock and the petrol flap for faults first before taking the vacuum pump apart. Try the test in my previous post to see if the Yellow vacuum pipe is sucking and blowing when locking, you could also remove the fuel flap Yellow pipe too, to test if it is sucking and blowing air when you lock/unlock.


Needs translated to English… Berliner SLK Stammtisch | www.BeStSLK.de - Trockenlegen der Pneumatischen Steuereinheit (PSE) Incl. Aus- und Einbau

Long thread here… PSE - Removal, Refit and Check - Mercedes-Benz Forum

Dec

Edit, I see in the diagram above, which is of a left hand drive car, the passenger door and boot lock share the one outlet from pump, 15 & 16 in diagram.

Try pressing the remote fob unlock button twice to see if that has any effect on the boot lock opening. Is your remote fob a flip out key blade type?

Sorry, missed this. Flipout key, Pressing key twice for passenger lock and that works fine.

 

[Dec]

So the boot lock should work as well as the passenger side (on a right hand drive)the share the same Yellow line at 16 & 15 in diagram.

Dec

 

[Jetl3on]

I will go with your suggestion and work on the basis it is the boot lock, thats the logical option right now, considering it was seized to begin with, never worked on a MB before, so fingers crossed I dont break anything.

 

[CaptainRAVE]

Mine would seize up all the time. Took a screwdriver to turn most of my locks when I got locked out...turn just enough to loosen.

 

[Jetl3on]

There is an American guide with pictures here... Mercedes-Benz SLK 230 Trunk Lock Cylinder Repair | 1998-2004 | Pelican Parts DIY Maintenance Article

Mark the lock screws with a marker to aid putting it back together.

Looking at my lock, these instructions are for the pre facelift, my lock looks different, the barrel is exposed once I remove the cover?

 

[Dec]

The link does say 1998-2004 but it is an American site.
Pictures of your lock, from different angles, would be useful.

Dec

 

[Jetl3on]

Here we go....

 

[Dec]

Completely different alright. Pictures very useful thanks.

As I see it, when the boot is slammed shut, 1 latches the latch on the boot floor, the boot is then locked. The only way the boot can be opened now is when air is blown through the Yellow tube 2 from the vacuum pump, the air pushes an actuator 3 in the direction of the Red arrow which then pushes the rod 4 in a certain direction, not sure exactly how, the rod 5 trips the lock in the direction of the Green arrow and the boot lid should lift up, powered by its springs.

If there is a leak in actuator 3 then the boot won’t open. Or there is something wrong with actuator rod 4 or rod 5.

The alternative to unlocking electrically, without air from the vacuum pump, is the turning of the mechanical key blade in the lock, as yours is seized then you have to free it up.

With the key blade in the lock… see lower part of picture… move, with gently force, the lever at the Blue arrow to the left or right, this is the part that is stuck/seized and it is this that is stopping the key blade from turning and unlocking.
The pointed end of the lever, at the Blue arrow, when it is turned with the key, also moves the actuator rod 4.

Dec

 

[Jetl3on]

Then my plan of attack must be the last part, if the key wont turn manually, then the CL wont move it either, with less force.

Excellent detailed plan, cheers.