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Boot lock failed on old W202

Discussion in 'Bodywork, Tyres, Wheels & Trim' started by rx6180, Nov 1, 2012.

  1. rx6180

    rx6180 Senior Member

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    Ageing W202 C200 with rust
    This morning my boot lock failed. Chucked something in the boot, went to the shops, then the boot wouldn't open when I got there. At first, I could hear the whirring of the servo (or whatever) when I pulled the internal release switch, and also if I pressed the external boot button with all four doors unlocked, but the boot stayed firmly shut. However now that whirring noise has ceased to be when it comes to the boot, though all four door locks are working normally.

    The whirring sound stopped happening after I'd hammered the mechanical part of the key into my boot keyhole. I found out last year that the never-before-used key lock on the boot was partially seized after I tried it for fun and found the key didn't go all the way in. Even a dousing of WD40 didn't help so I gave up. Now the key goes in (I only used a light tack hammer and worked the key in and out before it went all the way down) but the surprise-surprise, the lock barrel won't turn.

    Since I've a limited understanding of how the boot release works, I'm not sure what component initially failed to prevent the boot opening, or why the servo noise has now stopped, or whether I'll be able to open the boot with the button if I can get the lock to turn. I wondered if I'd blown a fuse somewhere but manuals and handbooks seem little help in isolating the fuse, other that to tell me fuses are located in two areas under the bonnet and...in the boot! The problem occured only an hour before I had to go to work and I've got home in the dark, so no time to further investigate.

    Does anyone know if the boot lock barrel turns anti-clockwise, or clockwise, to unlock? After another WD40 dousing and an overnight stand I'm tempted to try pliers on the key in the morning.

    Thanks in anticipation.
    Mick
     
  2. television

    television Always remembered RIP

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    You need to spray some PTFE into the lock and hold something that vibrates on the key to shake all the levers down.

    The chances are the vacuum element is split and needs to be replaced, when all working fit a cover as in my signature
     
  3. OP
    rx6180

    rx6180 Senior Member

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    Thanks Malcolm. I'll have to buy some PTFE then. That's if it can get past the WD40 type stuff I sprayed in first (Wilko's own). I don't really have anything that vibrates which is why I was tapping with a hammer, as well as just trying to get the key in.

    But which way to turn the key? Anti-clockwise is logical but I've known the opposite to be true on other makes of car. If I force the key the wrong way it'll never turn.
     
  4. television

    television Always remembered RIP

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    I think the key should turn either way,1 to open and the other to completely lock.

    When you push the key in, the high points on the key push all the levers out to max, when the lock is free and good these tiny levers drop down into the profile of the key, the key can then turn, the idea of something that vibrates shakes the levers down again.
     
  5. CafeMB

    CafeMB Banned

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    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.
     
  6. television

    television Always remembered RIP

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    What I said was right for trying to open the boot as the vacuum locking element has probably failed, he needs to get into the boot before he can do anything.

    there is a good chance that the element is holed
    171 A 208 800 03 75 ELEMENT
    REAR LID

    [​IMG]
     
  7. television

    television Always remembered RIP

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    It could well be the same part broken as on your and thank you for that, but he still has to get it open
     
  8. OP
    rx6180

    rx6180 Senior Member

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    Well weather permitting I'm going to have another go at the lock on Saturday morning, never having any chance of looking at it on Friday. If I can't get the lock to turn I'll have to try taking all the back seat out.

    What concerns me more than the initial failure of the boot to release from either the internal switch or the button on the key, is the fact that after I used a small hammer to drive the mechanical portion of the key all the way down the lock barrel, in the knowledge that a previous attempt to just let it soak in easing oil had no effect, there is now no 'solenoid' sound from the boot area when the internal release is pulled or the key button pressed, whereas originally there was, its just that the boot didn't pop up. So now I reckon I must have broken something else by using force on the lock.
     
  9. television

    television Always remembered RIP

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    Can you hear the pump run for a short time after pressing the boot release
     
  10. OP
    rx6180

    rx6180 Senior Member

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    No. This is what I'm saying. It ceased to be after I'd hammered the mechanical part of the key into the obstructive boot release button, with the button going in and out as I was doing so. Prior to that (on initial failure of the boot to open) you could hear the pump run, but the boot remained firmly shut. Now all I'm met with is total silence. However, everything works A1 on the passenger doors.
     
  11. television

    television Always remembered RIP

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    I wonder if you have the hole behind the seats that will enable you to release the boot from in the car, there are post on here where this has been done.

    Member CafeMB has said how his locked failed, in this case you would have heard the vacuum element working, if you heard nothing but the pump ran then the element probably
     
  12. OP
    rx6180

    rx6180 Senior Member

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    It's chucking it down with rain outside at the moment again so I still can't get to look at it. The weather should improve later on. I'll give the boot lock about ten to fifteen minutes to yield to attempts to joggle the tumblers so I can turn the key, if not I'll start taking the back seat out to see if I can make any headway there. At the moment it feels a bit like I've got a Standard 8 or Austin Healey Sprite with no bootlid, but no access from behind the back seat either! :shock:
     
  13. OP
    rx6180

    rx6180 Senior Member

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    I found a post where someone went in through the parcel shelf after taking out the first aid kit. Looks like they used over a metre of 3/8" drive socket extensions to reach bolts on the rear lip of the boot lid aperture! I've neither the tools nor the patience for that! But that car seemed to have fuel filler flap failure too. I just had a panic and rushed to my car thinking I wouldn't be able to put petrol in it either. My fuel flap opens with the passenger doors as per normal. Phew!
     
  14. OP
    rx6180

    rx6180 Senior Member

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    I can confirm there is no way into the boot through the back seat, not without taking a chisel to the steel bulkhead back there anyway. From inside the boot you can just see black plastic, and someone told me that on an Avensis (he worked for Toyota) that shroud just unscrews. Not on a Merc! The bootlid lock won't yield, so it looks like through the First Aid kit method. Seems like Mission Impossible to me. Already ripped the plastic tray out to find three rectangular holes in the steel shelf and a view of the plastic screw covers I need to magically remove, by torchlight, three feet away with tools I don't yet posess. Yay for electronic bootlid releases.
     
  15. taxii

    taxii Senior Member

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    Right just read the thread and been out and looked at mine and although mine's the earlier switch blade type key I would think the locks would be similar and clockwise turn on the deadlock and anti clockwise unlocks regardless of the other doors being locked. If it was me I would think stuck lugs on barrel so a few light tap's with a rubber mallet might be enough to loosen them enough for the key to turn. The first thing I do when I buy any car is to clean all locks and wdf them and all the hinges.
     
  16. CafeMB

    CafeMB Banned

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    The lock itself should be able to be opened using the key, even though the vacuum release mechanism sounds knackered. The lock should release mechanically like that.
     
  17. OP
    rx6180

    rx6180 Senior Member

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    Yeah I know! Fourteen year old car, lock never used because it works by remote, remote fails, lock seized up from lack of use!

    I'm now in. Tunneled my way into the boot via the rear parcel shelf. Made a right mess of the metalwork in the process, and forty quid down after buying lots of rachet extensions at Halfords. Now have an open boot but no lock on it to secure it after I removed the darn thing to see whats up with it. Light now fading outside so it'll soon be game over. I'll fill in all the details when I know more. There might be a few more useful tips to add to guide others, but it wasn't easy and there's been a lot of bad words used.
     
  18. television

    television Always remembered RIP

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    You can buy a new lock barrel from MB and not expensive,,,,must say you have done well,,, you can check the vacuum element now as well
     
  19. OP
    rx6180

    rx6180 Senior Member

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    I was quite destructive with the rear parcel shelf under the first aid kit. I had to cut a significantly large hole in the metal with tin snips, mainly because one of the bolts I needed to undo was not central in the oval access hole in the plastic shroud, and I struggled for ages with my collection of extension pieces and slim, long 10mm socket, eventually just managing to get on the bolt head by coming at it from an angle through my enlarged access hole, and banging the end of the link of extensions with a hammer.

    I also had the plastic covers fitted over the bolts at first. I got rid of these - after a fashion - with a medium sized screwdriver tightly tie-wrapped to a broom handle. Lots of fiddling trying to prize and push with a screwdriver on the end of a long broom handle. Finally I pierced the right hand one and it came out on the end of the screwdriver blade. The other one pushed in over the bolt head. I finally got rid of it after a struggle using a metal hook, made from the bent-over tang of a tiny rats-tail file, tie wrapped to my broom handle instead of the screwdriver. The plastic plug didn't pull out but I managed to dislodge it sideways and eventually pushed it out of harms way with my home made tool.

    The whole process was very frustrating and time consuming but in view of the fact the lock barrel wouldn't co-operate, there seemed no alternative apart from taking the car to a garage and letting them probably do much the same at whatever rates they charge.

    I'll upload some photos I took in a few days which might assist someone else who finds themselves in a similar position. I didn't show my old car much mercy, partly because it isn't worth much, partly because it had annoyed me with it's boot opening failure and partly because I had some real issues doing the job. Maybe my pics will show a 'real world' situation rather than, 'in theory, you can open the boot by unbolting the locking ring from access under the first aid kit'. It seemed impossible, it wasn't, but it fought me.

    Annoyingly, when the lock itself was dangling by its wires and vacuum hose as I took it out of the by now, open boot lid, somehow I pressed the boot release button on the key in my pocket by leaning on something, and the dammed vacuum mechanism operated!!!:eek: However I don't think this is the be-all-and-end-all because it still didn't release the square ring I'd just battled to unbolt, so I still think I've got the original failure problem.

    In fact, I'm a bit baffled by the lock barrel/vacuum actuator mechanism. When the actuator started working again, when the key in my pocket was pressed, the white cam-thing with a slot in it moved. In the slot sits a rather flimsy looking tin lever with a 'T' handle head, and this seems to move up and down and do nothing. At one point soon after removal, I split the lock into two basic parts, the lock barrel with actuator and the latch mechanism, with which that flimsy 'T' handle stays. I can set the 'latch' to closed with a screwdriver, then ping it open by lifting a white nylon lever down inside the latch mechanism, but that tin lever seems to play no purpose, yet it is that which seems to attach to the slotted cam actuated by vacuum. Also without a functioning lock barrel, I'm also at a loss to understand how the push button works when 'unlocked', to release that spring loaded latch. If I can coax the old one back into life I'd sooner do that, though if a new MB lock is the only route then it'll have to be. On the face of it the failure seems to be, as yet, undetermined. There certainly doesn't seem to be a leaky air pipe.
     
    Last edited: Nov 4, 2012
  20. television

    television Always remembered RIP

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    I think that is you lubricate well all the moving parts with some thing better than WD40 it will be OK,,,, there is that spring loaded part that stays in in the fully locked position (push press button in and you feel nothing) and that part should return to make contact with the button or it will get stuck again.

    As long as you leave it with the press button feeling the locking it should open,, some how it got stuck in the totally locked position, that is used when the car goes in for service .

    Not easy to explain
     

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