UPVC Door multipoint lock mechanism replacement have to be the same?

9 Mar 2019
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United Kingdom
I'm a novice at this, but I'm pretty sure that the gearbox is broken in the lock mechanism on my UPVC front door.

It's an older lock mechanism I think, two rollers (one top, one bottom) and a deadbolt.

The handle won't lift up to move the rollers. I can still lock the deadbolt with the key.

My question is, do I need to find the same mechanism gearbox and replace like for like, or can I get an entirely new mechanism with more lock points, and add the necessary catch parts to the door jamb?

Also, I have bought a new cylinder for the door. If I try to replace this before I get a replacement gearbox, is there a risk that the gearbox could further break when I remove the old cylinder?

Any advice would be appreciated.

Many thanks,
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It would certainly make your life a lot easier if you can get a direct replacement but I know this isn't always the case as some of the older gearboxes are now being discontinued. Some of the replacements by the same manufacturer can require a little ' fettling ' sometimes to get them to fit properly , but it is certainly doable. Search up Yale Lockmaster Universal replacements, relatively easy to fit .... look around though as some come with the keeps for the door frame side , others don't. Depending on what you purchase ( and what you currently have ) you may find you need to drill parts of the frame and/or sash.

As goes the cylinder , its unlikely to cause any more damage , as all the cylinder barrell does is ' throws ' the deadlock bolt .

Sometimes , and I do mean sometimes , it is possible to repair a damaged gearbox by opening it up but just bear in mind they are springs and small bits that will move once opened...if you do try , take lots of pictures before you disturb any of the internals of the gearbox!#

Just as an aside , are you sure its the gearbox at fault? It may be one of the rollers is jammed, I have seen this before , along with locks that have ' hooks ' , customer thinks its all broken but just a jammed roller or hook. Does the handle pull up with the door actually open?, as again may be door adjustment required and the rollers are fouling the keeps
Hi Ronnie,

Thanks very much for your reply.

I can move the rollers freely by hand when the door is open.

The handle will not lift up with the door open or closed.

I should mention that this is a new house I have moved into, so I have never seen the lock operate properly. Do some mechanisms move the rollers with extra turns of the key?

So is the cylinder hole mostly enclosed other than the opening for the cam to throw the deadlock?

I have visions of springs and gears falling from the gearbox once I remove the cylinder :eek:
Does sound like possibly where the mechanism for the rollers meets the internals of the gearbox has broken or come adrift. The rollers should work as soon as you pull the handle up , the Barrel just throws the deadbolt and ' locks ' the roller mechanisms and handle in place.
Never known any parts fall out just removing a barrel ( not saying it can't happen ) but replaced a fair few barrels over the years!
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Thanks again.

So it is possible that the problem is between the gearbox and the rollers, rather than inside the gearbox?

I'll measure up again today and look for replacements online.

Maybe I'll see an easy fix when I open it and can return the replacement (wishful thinking), but I want to be prepared to avoid an emergency locksmith callout if possible :D
I would try to find a direct replacement gearbox if at all possible.
Take it out and make notes of any names, codes, numbers printed anywhere on it and then Google them.
Once you know the name Ebay is usually the cheapest place to get them

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