Clicking/snapping door locks

One of the typical ailment of the CX is the loud clicking of the door lock mechanism. I don't think I've ever come across a CX where the door stops doesn't make that hard clicking noise when opened or closed. This is simply due to an inferior, and also quite stupid, construction. The symptom appears typically more distinct on front doors and especially the drivers door. The construction wears down after only a few years of use. The best way to slow down the process is to make sure the construction is well lubricated. Once this is thoroughly done you don't have to lubricate it more than maybe once every third year, if even that. But first lets sort out those clicking stops... The holding mechanism main part is a 'shackle' that moves between a spring loaded cam to achieve the holding effect that holds the door in it's open position. The forces involved are immense. (Therefore it is essential that the mechanism is well lubricated.) Hence the wear and tear on the shackle and it's holder. At the open end of the shackle there is a metal plate to hold the shackle together to prevent it from being distorted and to make the snap function more distinct. This plate is, from factory, under dimensioned to handle the forces. [I don't know what Citroën thought of when they made this plate but is seems they've just taken some scrap sheet metal the same thickness as the body sheet.] After a few thousand or so movements of opening and closing the doors the plate tends to get twisted and the holes enlarged. This is when you start to hear the clicking/snapping from the mechanism. To cure this you need to manufacture a new plate of as a suggestion a somewhat more for the purpose suited dimensions. I would recommend using 4mm steel or equivalent (what ever you find it can't be worse than the original). The precision of the new holes in the new plate is crucial; ideally make them just the same size as the shackle so you get a press fit over the ends of the shackle. The shackle has a diameter of 6mm. If you manage to get a good press fit you most likely wont need the original lock washer. If you really want to make it properly you can thread the end and put a locking nut at the end. Also you should place the holes somewhat closer than on the original plate (distance between the ends of the shackle) to pull the shackle together. This will make the shackle creep over the cam reducing the snapping/clicking effect and also make the plate grip tighter around the ends. What is also common is that the shackle gets worn at the points where it's attached (see picture). To further improve you can turn the shackle around so that the end that used to be in the holder now instead is the cam doing the holding. Finally when reassembling the whole construction use lots of grease. The only grease we've found can take the tremendous surface pressure is Moly Slip Molybdenum based grease (dark grey goo). Normal all purpose grease won't stand the pressure and make the door creak. If you did a careful job you should now have virtually silent doors. Mind you the drivers door can be so worn that it is practically impossible to remove all noise, but you will at least have reduced it a fair bit. The result is very much down to your effort and carefulness. Good luck!

An 'upgraded' locking mechanism with the thicker locking plate (A). The holes in the plate are placed closer to pull the shackle ends together (B). Note the amount of grease used. The golden stuff is Moly Slip's 'CopaSlip'. This will prevent seizing in the future. The black stuff is MolySlip's Molybdenum based grease. Click on picture to get larger veiw
Make the distance 'D' somewhat shorter than the distance 'd' to achive the force 'F'. To secure the plate you can thread one end and then put a locking nut to hold the plate.

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