Front door lock - latch won't fully open from outside using key

[GravesendPaul]

Hi all

My uPVC front door has a multipoint lock (Lockmaster). The latch works fine from the inside, using the handle. However when trying to open from the outside by turning the key, the latch feels stiff and barely clears the strike plate. Takes a little force to turn the key sufficiently to open the door.

Any ideas before I take off the faceplate and remove the lock?

Thanks

 

[crank39]

Try turning the cylinder round the other way to isolate the issue, if it's still difficult outside then it's the gearbox but I can't think why it should play up from the outside, could be the outer half of the cylinder failing, not sprayed any wd40 in have you.......come on own up?

 

[GravesendPaul]

So I took the cylinder out and that turns fine on its own. I opened the gearbox and couldn't see anything odd or broken so sprayed a bit of lubricant on the mechanisms, reinstalled and it appears to be fine now!

Didn't look too dirty but I didn't want to start taking all the pieces off.

Cheers