745 backdoor lock lubrication?

On my 740 station wagon the back door lock cannot me operated with the key because of too much friction apparently between the plastic cylinder and hole in which it rotates. Maybe some MoS2-spray liquid hit it when I tried to dissolve a sticking screw at the backdoor wiper system. The central locking/unlocking works so that is the way I lock and unlock the backdoor now. The problem was worse during winter in earlier years I recall but now it has become permanent also during the dry and warm season. I have treid to lubricate with a teflon based spray from outside whithout effect. Does anybody have a solution for the problem besides changing the whole lock?

Viktor Weisshäupl, Vienna, Austria

Reply to
viktor weisshaeupl
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I had the same problem with my 240 Wagon, and the problem may not be in the cylinder as you think, but in the sliding mechanism that the cylinder operates. You would have to remove the inside panel to gain access to it, then remove the screws that hold the latching mechanism in place, disengage the link rod and take the whole locking assembly out. The cylinder remains in place. Then sand any rust off, grease the heck out of it, re-install and enjoy. The whole process took less than 1 hour. Good Luck

Arnold

Reply to
Arnold Perez

"Arnold Perez" schrieb im Newsbeitrag news:Btk6b.3968$ snipped-for-privacy@nwrdny02.gnilink.net...

Thanks for the input. What I wonder is, - where does the electric mechanism fit in. Is it working on the last members of that chain distant from the lock cylinder?

Viktor

Reply to
viktor weisshaeupl

Hi Viktor, when you take this thing apart you will see that the "cam" that rotates when you move the key, also has a rod connected to it, the rod is operated by the lock/unlock solenoid (or motor), so that you operate the locking mechanism either by the central locking or by the key. In any event, if I recall correctly, there was a piston that goes through a hole, and the whole thing was rusted shut, after some wire brush and grease, the whole thing was as good as new. The locking solenoid was on the right of the keylock.

Arnold

Reply to
Arnold Perez

Try a little K-Y on the backdoor lock ;-)

Reply to
L.A.

Hi Viktor, when you take this thing apart you will see that the "cam" that rotates when you move the key, also has a rod connected to it, the rod is operated by the lock/unlock solenoid (or motor), so that you operate the locking mechanism either by the central locking or by the key. In any event, if I recall correctly, there was a piston that goes through a hole, and the whole thing was rusted shut, after some wire brush and grease, the whole thing was as good as new. The locking solenoid was on the right of the keylock.

Arnold

Reply to
Arnold Perez

Those lock cylinders on the 700/900 are very corrosion prone. Chances are the only cure will be replacement, or you could just ignore it and trust the power lock not to fail. Even if it does fail, you can still open the tailgate from the inside, provided the child-proof lock is not engaged.

Reply to
Mike F

"L.A." schrieb im Newsbeitrag news:y5v6b.15532$ snipped-for-privacy@nwrddc02.gnilink.net...

What is K-Y ? Living in central Europe I don´t know what it is. We have sprays containing MoS2 for lubrication of rusted or corroded mechanical stuff. Is it something like that?

BTW it does not feel like rusted mechanics, it really feels like friction between the plastic parts of the cylinder which I interprete as possible consequence of oil dripping on it by accident.

Viktor Weisshäupl

Reply to
Viktor Weisshaeupl

K-Y Jelley is a lubricant in medical use (including sexual use). Much better to use either WD40 or Duck Oil.

Cheers, Peter.

Reply to
Peter Milnes

"Peter Milnes" schrieb im Newsbeitrag news:bjj9f0$p44$ snipped-for-privacy@titan.btinternet.com...

Which raises the next question - what is WD40? Any hints on the chemistry of that stuff?

Viktor

Reply to
Viktor Weisshaeupl

It is a special lubricant, waterproofer, contact cleaner, etc. that has been in use in the UK for many years. It was developed for the Armed Forces as a multi-purpose liquid not long after WW2. I used it when I was in the RAF servicing V-bombers.

Cheers, Peter.

Reply to
Peter Milnes

Most reports indicate it based upon kerosene (which you may know as paraffin, a liquid used as lamp and stove fuel). The real formula is a trade secret.

More indepth guessing can be found at:

formatting link

Gary

Reply to
Gary Heston

[ ... ]

It first appeared on store shelves in 1958, five years after it was invented in 1953--a good bit after WW2. When were you in the RAF?

WD-40 history:

http://www/wd-40.com/AboutUs/our_history.html

Gary

Reply to
Gary Heston

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