W140 S Class boot not closing flush

Mazi

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Ive just bought a 1998 W140 S320L from a freind of the family who owned it since new. The bootlid does not close flush no matter how hard you slam it.
I dont know if the problem lies with the self closing mechanism.
Anyone got any ideas?
 

shayes

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Hi Malcolm,
I've got to look at my boot lock mechanism as may be cause of battery drain. Not had chance to test those fuses.

It does not unlock when supposed, and does lock when not suposed to. The diagram shows a handle which I don't have on my car and don't see S320 listed on the diagram. Not seen any adjustable bungs. My guess would be for the mechanism in the lock to be undone and re-positioned lower to solve problem. Three Star bolts from memory. Take out boot trim fasteners with screwdriver and you can get to the lock bolts.
Slamming boot aint gonna help the closure system thats a certainty!

ps beg pardon S320 is listed.
 
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Mazi

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You have a bung each side, 47 in the link, one my be set wrong stopping the lid from seating correctly

http://www.detali.ru/cat/oem_mb2.as...GM=717.454&CT=F&cat=19B&SID=75&SGR=030&SGN=02

Could it be something to do with the self closing mechanism which I belive is vacuum operated. The reason I say this is that the gap on the bootlid is quite large when the boot is closed,it almost looks like the boot is open.
You can actually push the bootlid down further to is correct position but it just pops back up when you let go.
 

Dec

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Sounds to me like the “square ring” needs adjustment or tightening, picture is of a W202, don’t know how similar yours might be.

Dec

BootLock.jpg
 
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shayes

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Could it be something to do with the self closing mechanism which I belive is vacuum operated. The reason I say this is that the gap on the bootlid is quite large when the boot is closed,it almost looks like the boot is open.
You can actually push the bootlid down further to is correct position but it just pops back up when you let go.

Not sure what gap you mean. About a quarter of an inch all round, except at back.
If you take off the boot trim about six or eight small square fasteners, seen next to catch and at sides, removed by prizing out the centre part with an eighth inch screwdriver, you can then pull away the lining to reveal the bolts and the vacuum. As I say, I think the bolts do allow for positioning the lock clasp higher or lower. They need a star key to undo. You can also watch the vacuum to see if it works.
 

shayes

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Ive just bought a 1998 W140 S320L from a freind of the family who owned it since new. The bootlid does not close flush no matter how hard you slam it.
I dont know if the problem lies with the self closing mechanism.
Anyone got any ideas?

by the way, does the boot self close. Have you watched it self close when you pushed it almost down?
 

television

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Then should just be the striker plate set wrong
 

r129co

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If the boot does not self close have you tried moving the lever over thats situated in the lid above the vacuum lock.It has two positions...one allows the boot to close fully without the vacuum assist.
Carl
 

Wafter

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Mazi,
I've just come accross your post. I had exactly the same symptoms. If you have not yet managed to solve your problem let me know and I'll put you on the right track.

Regards
Alan
 

television

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Mazi,
I've just come accross your post. I had exactly the same symptoms. If you have not yet managed to solve your problem let me know and I'll put you on the right track.

Regards
Alan

When you unlock via the trunk lid by turning the key 20º to the left, does all of the car unlock within 3 sec
 

shayes

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I still have the boot problem but not one of failing to close properly.

Only the other day I phoned Merc Lancaster to hopefully source the part I need. Still unsure which part that is. Boot soft closes OK. Just does not lock when it should nor unlock when activiated via the fob and mirror sensor.
Don't think that the sensor in the boot works and may have something to do with it. I know I should read previous advice but its just something that I keep putting off.
Merc L sent me the boot lid exploded diagram. I know the slider for the locking mechanism had a guide rail clip broken but I fixed it so it slides. Which of the part number seen on the diagram do I need, I really can't work it out. Number 8 which contains the lock? Number 20 is that the sensor? I really need to get to grips with this problem as it does affect the number of times I have to click the keyfob to get the car to actually start. Feeling rather lazy at the moment thats my problem.
 

television

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I still have the boot problem but not one of failing to close properly.

Only the other day I phoned Merc Lancaster to hopefully source the part I need. Still unsure which part that is. Boot soft closes OK. Just does not lock when it should nor unlock when activiated via the fob and mirror sensor.
Don't think that the sensor in the boot works and may have something to do with it. I know I should read previous advice but its just something that I keep putting off.
Merc L sent me the boot lid exploded diagram. I know the slider for the locking mechanism had a guide rail clip broken but I fixed it so it slides. Which of the part number seen on the diagram do I need, I really can't work it out. Number 8 which contains the lock? Number 20 is that the sensor? I really need to get to grips with this problem as it does affect the number of times I have to click the keyfob to get the car to actually start. Feeling rather lazy at the moment thats my problem.

Does the pump run when you try and unlock the boot
 

shayes

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Does the pump run when you try and unlock the boot

I can hear a whirring noise from the boot when I get into the car but this maybe the Aerial motor going through the motions (broken mast).
I seem to recall when I repaired the slider that it seemed to get drawn across, but maybe that was when I was using the key in the lock.
Will need to check and maybe I can get away from the desk tomorrow - weather permitting.
 

television

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I do have details of all parts of the boot lock
 

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When you unlock via the trunk lid by turning the key 20º to the left, does all of the car unlock within 3 sec

Malcolm, the original problem as reported by Mazi is very typical of the closing assist pump not working correctly. My boot lid operated perfectly then one day it didn't and left the large gap as reported by Mazi. The boot opened and closed automatically with the key fob or the switch inside the car and locked OK, it was just that the soft close mechanism was not pulling it closed.

I have done a lot of research on this and I just wanted to help Mazi if he has not yet solved his problem.

Regards
Alan
 

television

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Malcolm, the original problem as reported by Mazi is very typical of the closing assist pump not working correctly. My boot lid operated perfectly then one day it didn't and left the large gap as reported by Mazi. The boot opened and closed automatically with the key fob or the switch inside the car and locked OK, it was just that the soft close mechanism was not pulling it closed.

I have done a lot of research on this and I just wanted to help Mazi if he has not yet solved his problem.

Regards
Alan
Hello Alan,,, I do have 4 separate pages for the components in the boot lock
Do you have the main function paper that describes it all,

I can send it to you
 

Wafter

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Hello Alan,,, I do have 4 separate pages for the components in the boot lock
Do you have the main function paper that describes it all,

I can send it to you

Malcolm, that is very kind of you but as everything is now working perfectly I have no need of it. Besides, I am not competent or brave enough to start dismantling things like locks!

As a first fix, and something Mazi could try, you can remove and then replace the number 9 fuse in the boot fuse box. This often re-sets the pump, providing it is working, and will give full operation back to the soft closing system, but only for a short time. A permanent fix is a little more involved. It gives full operation back because when the pump operates, and it pressures the doors closed rather than sucks them closed with a vacuum, it pushes until it reaches a pre-set pressure and then stops. However, if it does not reach this pressure for whatever reason in a specified time it cuts off and the electronics charge a 'time out' to that line. After two time outs the line is cut off permanently. Pulling the fuse causes a re-set in the system and it will work for a further two closes. If this happens then you have the reassurance that the system is basically OK and by doing a relatively simple tweak to lower the pre-set pressure you can make this fix permanent.

Interestingly, after the doors have been pushed closed, the pump then reverses and a vacuum is applied to the lines presumably to pull the actuators back in case the actuator springs do not do a full retraction for whatever reason. You can hear all this happen if you listen carefully - the doors are pushed in beyond their normal locking limit, the pump stops and the doors 'relax' and move out slightly to their normal closed position and then you hear the vacuum pump chug for a few seconds. It is marvellous to behold.

Regards

Alan
 

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soft close

alan am very interested in your fix for the above mentioned prob it does exactly what you describe plz can you forward details of "a how to?" many thank david
 
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