Multipoint Door Lock Lock 'gearbox' Replacement

This door and it's lock is probably abou 22 years old. It's the type where you have to lift the handle to engage the 3 point locking mechanism. Recently this lifting started to get more difficult sometimes sticking and requiring several attempts to make work.

Note: The removal/replacement process may have to be done twice. First time to identify the problem and the make/model to order.

Subsequent to doing this I came across these youtube video guides for uPVC door lock replacement which it would be useful to view before doing this. https://www.youtube.com/watch?v=usEivKYL... https://www.youtube.com/watch?v=nEDbRB27...

Remove door edge cover. Keep the screws somewhere safe in the order they are fitted so you know where to put them back.

Sorry about photos, getting a clear edge on photo isn't easy.

Remove the retaining screws from the moving part of the locking mechanism again making sure you know where they came from. There were only 2 on mine.

Take care as the parts become loose as the top and bottom catches are only held in place by the cover , you may want help here. Remove and place out of the way.

Remove handle retaining screws and then carefully take handles off from both side taking care not to lose the operating shaft and any other parts.

Remove cylinder lock retaining screw and then remove lock making a note of which end is outside.

Gearbox can now be removed. First time around this may simply to be to identify the problem and/or identify the make/model for replacement.

In this particular case there was cracking around the 'barrel' that takes the handle shaft which was causing the sticking.

To identify the make/model required for replacement I spent ages on Google. You need several key measurements and by studying various lock supplier websites I found it was almost the same as an older model Fullex type A.

Close study of the pictures on the websites seemed to show that the very top and bottom mounting points may be slighter thicker than mine. But I thought it to be a low risk as the door is wood cored I could chisel a bit out if neccessary.

When the new gearbox arrived there were a couple of plastic inserts that had to be removed. Don't forget to do that before installing (unlike me!).

Also note the latch came fitted the wrong way round but was easily rotated using it's screw.

A quick bit of chiselling allowed the new gearbox to fit.

As a precaution I greased what I thought would be key points of wear.

All that is left is reassembly by reversing the steps taken.