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Lockmaster Milamaster Door Lock Replacement uPVC Gearbox 35mm Backset


Lockmaster / Milamaster Door Lock Gearbox Centre Case

Single Spindle

A replacement centre case for the Lockmaster / Milamaster door lock. If you're having problems with your door lock, the gearbox is almost always the problem and changing it is as simple as removing a few screws.

Product Information

  • Important measurements: 35mm Backset / 92mm PZ Centres
  • This is the mechanism inside the door that is operated by the handle.
  • Most likely to be the problem when a lock fails.
  • Reversible latch for left or right handed doors
  • Single Spindle - for lever/ lever operations


Write Review

  1. perfect fit 5

    Posted by Alanspeed on 13th May 2019

    Was not sure about the size, Looked at the photos which explains how to take the measurements ordered and it fit perfectly. Twenty minutes and it was fitted and working and at a very good price.The customer service was spot on and quick delivery Well done GB store

  2. Fitted perfectly! 5

    Posted by j on 12th May 2019

    Was quoted £120 to replace gear box.
    Purchased this, like for like, for £18.99!
    It took me less than 30mins to remove old gearbox and replace with new. (I’ve never fitted one before) very pleased as it fitted exactly and door works like new again!
    Prompt delivery, great price, saved over £100!
    Thank you GB DIY store!

  3. Well pleased 5

    Posted by Dennis Camwell on 11th Feb 2019

    After door locking and unable to open, I had to require locksmith to gain entry, cost was fair, for his knowledge, but I was horrified when he told me he had to replace the whole thing, could not just change gearbox quoted £240, just did not have that amount, but looked on Internet found GB DIY paid £19, recievd two days after fitted it myself took 20mins, and one very relived and happy customer