Boot lock failed on old W202

[rx6180]

Certainly isn't straightforward to understand. I can't afford to leave my car with just a bugee cord holding the boot shut for more than two or three days, and I won't willingly go through what I went through yesterday again, by putting a lock back on that is likely to fail.

 

[television]

What is hard to know is the vacuum element pay have a hole or be split, operating under no load is a different cup of tea to operating the lock when all pulled down, they cost about £18 from MB

 

[rx6180]

I'm going to my nearest MB spares counter in the morning with the pile of bits I took off. I'll no doubt end up buying the latch, vacuum actuator and lock barrel. To be honest, the mounting plate of the latch part has a stress crack in the metal on one side, though it isn't right through yet and I bet a blob of weld would make it (that part at least) fully serviceable again. However since I've got to buy some new parts anyway, I may as well see how much all the bits are going to cost me. What I do not want to do is put the other one back and end up in the same position as I was yesterday. I'd be quicker releasing a stuck boot on this car next time as I've done all the damage I needed to inflict already, but I still don't want to risk going through it again.

 

[rx6180]

Right. Here is my effort to contribute to the description of how to get into a jammed shut boot on a W202 by going through the rear parcel shelf.

The original guide, posted by someone else, I found on this forum on this page.

http://forums.mercedesclub.org.uk/showthread.php?t=60071&highlight=boot+lock&page=2

It shows pictures of the rear parcel shelf minus the first aid tray, and the bolts that need removing from the striker plate in the boot, in order to get the boot lid up, so you can carry out whatever repairs are needed to the lock. It also shows how the bolts can be covered by a little plastic cover, but it doesn't suggest really how you can get these off from over three feet away working through a little hole in the rear parcel shelf while kneeling on the back seat. To me it sounded impossible but I was left with little choice but to try it.

So firstly, this is my rear parcel shelf minus the first aid tray. Normally you can see three rectangular holes pressed in the metal, but after examining the kind of view I'd got of the bolts I needed to get at, at this stage still covered by plastic blanking plugs, and considering the tools I had at my disposal, I wasted no time in reaching for the tin snips and opened out the holes into one bigger one.

The next photo is a view through the same hole, with me kneeling on the back seat (actually the rear seat squab was out of the car as I'd tried to see if there was a way into the boot through the back of the seat first - so I was kneeling on the sound deadening. I left the seat squab out to prevent damage). I'd already been giving the plastic bolt covers some grief at this stage and one of them is off. The other is already slightly damaged from my efforts. You may also notice that the visible bolt head is NOT in the middle of the oval access hole. This caused me considerable difficulties in getting a 10mm socket on the bolt head.

So what tool did I use to get the plastic covers off the bolt heads? This initially.

This is a flat bladed screwdriver firmly tie-wrapped to my yard broom handle. Obviously I cut the tails off the tie wraps before using it. This was my second fixing of the screwdriver to the handle, as the effort in removing the first plastic cover dislodged it. After spending ages trying to get my screwdriver blade under the edge of a plastic cover and scrape it sideways, trying to illuminate the area at the same time with a hand-held Mini Mag-Lite, frustration got the better of me and knowing that at that moment my 'driver blade was resting centrally on the 'right' hand screw cover (looking into the boot from my vantage point) I dropped the torch and pushed on the broom handle with all my might, trying to break the cover. Instead I pierced it through the middle and it came out speared on the end of my screwdriver blade. I wasn't so lucky with the other one. That one pushed inward at the top and was left partially obstructing the bolt head I needed access to. Eventually after failing to make any further headway with my extended screwdriver, I rummaged in my tool box and tie-wrapped a tiny broken rats-tail file to my broom handle, a file that had had its tang bent round into a hook shape.

I wanted to try to hook the cover out but that didn't work either, but more by accident than design, the narrower hook pushed the plastic cover sideways and in the end it disappeared somewhere inside the plastic shroud that covers the metalwork at the back edge of the boot.

So, bolt heads revealed, knowing I didn't posess 1 metre of 3/8" drive rachet extensions, I set off to Halfords and ended up buying two lots of 'Professional Locking Rachet Extensions' for £19.98 each. These each contain something like (off the top of my head) a 10", 7" and 4" extension so each set came to just under 2ft in length. Someone later told me Snap On do very long one piece extensions but I bought what I could find, and I was pleased they locked together because if they were normal ones, I'm sure during what followed I'd have lost part of the assembly inside the boot, and I would have probably taken a crow bar to the boot lid instead.

The 'left hand' bolt came off relatively easily, accepting that I spent quite a while with my wobbly assembly of rachtet extensions and torch, trying to pick up the head of the bolt. The first time I used the rachet I thought I slipped and had rounded the darned head off. The socket needed to be a slim, extended 10mm socket. A normal one did not reach far enough through the oval access hole to be able to pick up the head of the bolt. Thankfully I had the correct type of socket in my existing Halfords socket set, because I didn't see any in the shop when I bought my extensions. As mentioned earlier, the right hand bolt was a pig. The socket just would not go on the bolt head because it wasn't in the middle of the access hole. I tried fitting a hacksaw blade to my broom handle and tried to cut the plastic divider between the two oval holes, but that didn't work because unknown to me at the time, the metal 'D' ring of the striker plate was right behind so I was trying to cut hardened steel too!

Finally I'd had enough and the tin snips came out again and I made a bigger hole in the parcel shelf. you can see the result in the next pic, taken AFTER I'd finally managed to undo all the bolts and open the boot.

I made a bit of a mess, didn't I? By this stage I didn't care. I managed, JUST, to come at the squiffy bolt head at a bit of an angle through the enlarged hole, and as soon as I thought the socket 3ft away from me was slightly engaging with the flats of the hexagon bolt head, I reached for the biggest hammer I'd got with me and banged on the end of my chain of extensions to drive the socket over the head of the bolt. By some miracle it engaged and when my rachet was fitted to the extensions I was able to turn the bolt and as it loosened, I finally began to see daylight appear around the edge of the boot lid from my vantage point, looking through the ragged hole in the rear parcel shelf.

I still think so many rachet extensions plugged together, to reach bolts so far away, seems unlikely to work, but after a battle it did.

And here, with the boot now open, is the bit that I liberated, still firmly clamped in the jaws of the obstructive, non functioning boot latch mechanism.

At this point I still need to obtain new boot lock parts. I'm unclear as to what the original malfunction was, but the actual lock barrel is knackered anyway. As for the damage to the rear parcel shelf, with thick gloves on I worked the ripped bit of tin hanging down, backwards and forwards till it broke off, flattened the remaining steel out as best as I could, then taped over the holes, both sides, with heavy cloth tape. With the first aid tray back in the car it looks okay from the inside, and you never normally look under the back window in the boot anyway so that part is out of sight. Some of the plastic clips on my first aid tray broke while getting that out, but its gone back in okay. Until I get a new boot lock, my boot is being held shut, not very effectively, by a bungee cord passed through the vacant lock barrel hole, and hooked under the back valance.

Not what I'd call a pleasant job, and I used some very improvised tools. More than once I stood at my shed door staring blankly at what was in there, trying to think what I'd got that could reach 3ft through a small hole and take plastic covers off or centralise a bolt head. But if anyone else is stuck like I was, it can be done, but get locking extensions or one big one (if Snap-On do make one) and you might have to make you parcel shelf hole bigger.

 

[television]

Thank you for the pictures and the write up, great DIY stuff

This should go in the DIY section

 

[CafeMB]

Might have been easier to drill the lock barrel instead?

 

[television]

Might have been easier to drill the lock barrel instead?

You still could not open the boot, plus they are pigs to drill out, the drills jam and snap

 

[CafeMB]

You still could not open the boot, plus they are pigs to drill out, the drills jam and snap

You could if you used a good quality drill bit and drilled multiple holes, the outer part of the barrel is plastic after all and would give after enough drilling. How would locksmiths get in?

 

[television]

You could if you used a good quality drill bit and drilled multiple holes, the outer part of the barrel is plastic after all and would give after enough drilling. How would locksmiths get in?

To drill the barrel out you have to start with a small drill in the center, , the center has the slot for the key and a 1.5mm drill is about the largest to start off with, the drill has nothing solid to keep it central and the bit jams in the levers.

No point in drilling all round the circumference there is nothing there would help.

I am pleased that you can do it that way

 

[rx6180]

I've been to the parts counter this morning, and have been told the lock comes as a unit and would cost me in excess of £200, plus in my haste to get there before work I forgot to take my log book and several types of I.D. with me, because buying locks is a security issue. No matter because when I was told the price I refused to pay it.

If I can't do anything with my existing lock, which would of course be totally useless if I'd have drilled it out, I'll have to try a breakers. If it comes to that, and I get no result there, I'll fit the old lock back, slam the boot shut, and get rid of the car. I've got to the stage where I'm not prepared to spend something like 200 quid for a lock on a car of that age and of such low value. It is a shame because it has served me well (but been expensive to repair sometimes) and it still runs very well, but it is showing its age now on the bodywork, and I think I might be due for a run of mechanical failures. I've been thinking about looking for a newer car, and this might be the incentive I need to do it. I'll have to see how it goes; I've not given up yet, but £200 for a lock is out of the question. That is about how much a dealer would be likely to offer me for the car, in part exchange, I think.

 

[television]

I've been to the parts counter this morning, and have been told the lock comes as a unit and would cost me in excess of £200, plus in my haste to get there before work I forgot to take my log book and several types of I.D. with me, because buying locks is a security issue. No matter because when I was told the price I refused to pay it.

If I can't do anything with my existing lock, which would of course be totally useless if I'd have drilled it out, I'll have to try a breakers. If it comes to that, and I get no result there, I'll fit the old lock back, slam the boot shut, and get rid of the car. I've got to the stage where I'm not prepared to spend something like 200 quid for a lock on a car of that age and of such low value. It is a shame because it has served me well (but been expensive to repair sometimes) and it still runs very well, but it is showing its age now on the bodywork, and I think I might be due for a run of mechanical failures. I've been thinking about looking for a newer car, and this might be the incentive I need to do it. I'll have to see how it goes; I've not given up yet, but £200 for a lock is out of the question. That is about how much a dealer would be likely to offer me for the car, in part exchange, I think.

Do ask member Rob Parker if he has one plus loads being broken up now says, you might find it easier to free up your barrel now the lock is off, and transfer it to the new one

 

[rx6180]

Progress! Of a sort. Most importantly, I've got my lock barrel working with the key. That wouldn't be the case if I'd drilled it. Okay, I've slightly butchered the odd bit of plastic in my attempts to get the thing out of the mechanism that surrounds it, but that does not appear possible. It must be pressed into its plastic surroundings on a machine, complete with return spring, and once in, that is it. I exposed the inner end as much as possible though, by removing the white nylon cams on the end of the barrel, held by a spring circlip, and ran Plus Gas Dismantling Lubricant down inside where the tumblers are, flooding it till liquid ran out of the key end. Then I used the key blade with an adjustable spanner across it applying pressure in a turning motion, and tapped on the end of the spindle I'd taken the cams off, with my toffee hammer. I was holding the lock in one hand, the hammer in the other, and the handle of the spanner was pressing on my belly. A vice might be easier. Oil sprayed on my kitchen work surfaces too. But working the key this way and that, it eventually yielded and I was very surprised. Must be the Plus Gas that did it. First it moved, then stuck again, then moved, then stuck again, and each time the key was removed, at first the lock stuck once more. But with persistance it finally became fully functional. So I should be able to operate my boot lock manually with the key.

And on that theme, I've gained some insight as to what does exactly what with this mechanism. Too complex to try to explain fully, in simple terms a tinny little lever I described earlier as seeming to have no function, has broken on my boot latch. THAT is the original failure. This lever does by remote control what the unlocked push button does with a finger press. I still don't understand ALL the ins and outs of this lock, but I found a tiny piece of metal, stuck down with grease, that has fallen off the end of this tinny lever, hence it no longer has a function. It is such a pathetically fragile looking bit of kit that I'm surprised it has lasted this long. Also, my metal latch part has a stress crack across an area close to the mounting bolt holes, which isn't good, though maybe a blob of weld might secure it.

Malcolm, I may well contact the person you mentioned (although I don't know him at present) about secondhand spares, but in the short term I should be able to re-assemble my boot lock and use it with the key. As far as I know, the vacuum parts are okay.

I could photograph my bits to put on the thread, including the part that failed, but not tonight as it is too late.

 

[television]

That would be good to see the broken part,,, best of all you now know what happened .

Rob is very good at "three pointed parts" this would make a very good DIY

 

[CafeMB]

in simple terms a tinny little lever I described earlier as seeming to have no function, has broken on my boot latch. THAT is the original failure.

Buy a second hand lock mechanism and switch the barrels over, it will cost the princely sum of £10. The lock will then work again. I knew that this was the problem when you mentioned it because I did this on a friend's car.

 

[rx6180]

Update. This is the part that broke, a lever made of very thin metal.

The 'T' bar at the top fits into the slot on this white plastic cam, operated by vacuum when the key or internal boot release is pressed...

...and when the cam moves, it is supposed to pull the thin metal lever, which at it's other end (the broken end on my example) is somehow attached to the horizontal bar highlighted by my ball point pen on the actual boot latching mechanism.

The white plastic lever on the same mechanism, pivots and lifts the same horizontal bar to release the boot when the unlocked boot release button is pressed, as the alternative to using the remote releases.

This is the stress crack I found in my latching mechanism, though this has nothing to do with the failure of my car boot to open. As a short term measure to get a lock back on my boot ASAP, my local garage welded it while I was at work and I pick it up tomorrow.

And of course it has been prised out of its plastic shroud, which is all you usually see of the boot latch.

This is the end of my lock barrel that was inaccessible until I got my boot open and dismantled the lock...

...and these are the cams and levers I removed to make it easier to put lubricant into the tumblers inside the barrel. Strictly speaking the white sleeve didn't need to come off and I broke a bit of plastic in the process, but it'll be okay. I was trying to get deeper into it than I needed to.

These tools, the blade of my old car key, and Plus Gas Dismantling Lubricant were what I used to finally free up my lock tumblers. I used the hammer to tap on the end of the shaft the white cams came off, while trying to turn the adjustable spanner.

If I use the car key to unlock my boot from now on (when I eventually get it back together) it is obvious than the old design key was made to be more practical to use like a real key, than my more modern replacement which has no method of holding the blade for greater leverage. I've only got one key like the black one, the other one failed years ago and I was told to buy a new one and keep my remaining working old key as a spare only, as my M-B dealer reckoned electronic keys are only rated to be good for seven or eight years.

 

[rx6180]

The boot lock mechanism is now back on my car and working with the mechanical key, six days after it failed remotely and sealed my boot shut due to the seized lock barrel. Unfortunately my local garage didn't weld the crack in the latch mounting plate for me yesterday, as they told me they were out of gas and had gone to get some this morning when I called. But I wanted to put the lock back together and fit it to the car as I was running a risk on several levels by driving around in a car with a boot lid almost, but not quite completely, held shut by an elasticated bungee cord off my bicycle luggage carrier. A secondhand latch is certainly on the cards now, but at least I can close and lock my boot lid.

I pretty much sussed out the functions of the lock and what its components do. In fact I didn't have it all completely right until I had it all back together, but now it has all become clear. Not sure if it is explained fully in the car's handbook, because I never looked when my boot jammed shut with a seized lock barrel, I just fought my way in and then set about trying to replace/fix the knackered lock. But later I can supply a few pics and an explaination of how the thing works if anyone is interested. I certainly didn't understand what the key blade was supposed to do having been pressing electric buttons for the last nine years, and then finding the key would not even go in the lock, let alone turn. Turning the key one way locks the boot so it doesn't even open by remote control, turning the other way AND pressing in at the same time pops the boot open. I did not expect that.

I also checked my drivers door lock, that had the plastic plug in it. First time ever on a near fourteen year old car. With the plug out and key in, the tumblers sounded a bit dry, but the lock worked fine. Thinking WD40 might be a bit thin and searching as a long term lubricant, I kept running the key in and out of the lock with some 3-In-1 type oil on the blade, and it has softened it up.

You need to defeat the alarm with the remote on the key before using the mechanical car door key or boot release key though, otherwise the alarm goes off. Probably not an issue if your reason for needing the key blade was a discharged battery!

 

[television]

PTFE coats all the levers and it does last where as WD40 dries out, I have used PTFE on all my cars and never have any trouble, they all go silky smooth as the levers get a coating

 

[rx6180]

I believe you, it's just that I've neither looked nor previously come across PTFE in the form of a spray and until you mentioned it, I never knew it existed. Based on the evidence of the door lock though, if I ever go back to using the remote boot release, one of those black plugs will give good protection to the lock barrel. A better idea would be to use it periodically with the key though. I just never thought about it till last year, then found it seized up when I tried it.

It has come to my attention that most cars younger than mine either have a boot/tailgate key hole mounted higher up and off centre to where the actual latch is (typically alongside the number plate) or have no key hole at all, including Mercedes cars. Presumably these are totally dependant on an electrical release mechanism. So I guess when that breaks, you are totally stuck. In fact it happened to my stepfather with a Citroen C4, although I think he could gain access to the luggage area through the back seat, with it being a hatch. I seem to remember the cause was frayed wiring with the constant opening and closing of the hatch lid, and it cost quite a bit to put right. That C4 turned out to be a very troublesome car actually. He hasn't got it now. He drives a diesel SEAT, which is basically a VW Golf.

 

[rx6180]

I found it quite interesting working out how this boot latch worked, seeing as I was forced into it by it packing up, and previously knowing nothing about it. I couldn't find the information elsewhere. Until I knew how it worked, I didn't know what was broken. I also didn't understand what was meant by the key turning both ways - 'of course it does' was my thought, to lock and unlock, but I didn't know it turned clockwise to deadlock the boot, and anti-clockwise to open it manually, from the centrally upright position.


This is my lock barrel with the white plastic cams, levers, whatever you want to call them, put back on. They needed to be tapped down slightly with a hammer and small drift to get them to seat below the circlip groove.

With the key turned clockwise, so the slot is horizontal

the cams move to push on this spring loaded lever (the upper most white plastic part)

which moves across to block the movement of the vacuum operated lever

that operates the boot latch by remote control, therefore the boot is 'deadlocked' and can't even be opened if someone breaks into the car and uses the boot release switch in the console.


With the key turned anti-clockwise to the 10 o'clock position, against spring tension, and pushed in (the key cannot be taken out in this position)

the cam lever moves downwards

and with the boot release button pushed in, presses on this white plastic pivoting lever

to lift a bar and release the spring loaded boot latch, a job performed by this tinny little lever

when the electronic/vacuum remote boot releases are used instead. The lever is supposed to fit down a slot where I'm holding it in the photo, but it is broken and doesn't work.

These are the two halves of the latch and barrel mechanism put back together (minus the tinny lever)

AND THIS...is what the underneath of my rear parcel shelf looks like after I taped over the big ragged hole I made to get into the boot with socket extentions after the lock packed in.

It isn't too bad. Actually I could have taped it up neater but on the day, I'd had enough, light was fading and it was getting cold outside. I just wanted to tidy up and get done. You can't see this anyway unless you kneel down at the back of the boot and look up, or are lying in the boot, which is what I was doing when I taped it up.

Oh well, someone might find this useful in the future.

 

[rx6180]

Thats not quite right as Malcolm said. The locking mechanism on the 202 has a lever which attaches to the vacuum line. The vacuum mechanism doesnt break, it is this attachment which goes over time. You just need to buy a new lock, dont worry about it not being the same as you will need the working plate and lever to get yours functioning again. You just switch the barrel mechanisms over and refit it and your boot should open and close.

I did it on a 202 I used to own. It's not as simple as spraying PTFE as it wont help with the lock opening and closing.

So did the the 202s you worked on have lock barrels that still opened the boot, when the thin little lever broke internally? You did say it was a lever early on, but without pictures it was hard to visualise what you meant, just as I didn't understand the deadlock function even though it had been mentioned on this thread. I needed to get my lock barrel moving again and put all the bits back to figure it out.