I was called out to a property in Paisley after the customer discovered she could no longer lock her uPVC door. Concerned about the security of her home, she asked if I could attend as soon as possible.

After inspecting the door, I quickly identified the problem as a failed gearbox within the multipoint locking mechanism. Fortunately, I carry an extensive range of replacement gearboxes and locking components on my vehicle, allowing me to complete many repairs during the first visit. Can a Faulty Gearbox Be Repaired? explains why replacing the gearbox is often all that's needed.

Diagnosing the Fault

Once the locking mechanism had been removed from the door, it was clear the gearbox had failed and required replacement.

After fitting the new gearbox, I tested the mechanism before refitting it. During this process, I noticed the bottom hook still wasn't operating correctly.

A closer inspection revealed that the hook had seized through wear and contamination. Rather than replacing the entire mechanism unnecessarily, I removed the hook, cleaned it thoroughly and refitted it. Once reassembled, all of the locking points were operating smoothly again.

The Underlying Cause

Before completing the repair, I always check why the original component failed.

In this case, the door was catching on both the top and bottom of the frame. The door had gradually moved out of alignment, placing unnecessary strain on the gearbox every time the handle was lifted.

Over time, this constant pressure had almost certainly contributed to the gearbox failure. Can a Dropped Door Damage the Lock Mechanism? explains how poor alignment can significantly shorten the life of a multipoint lock.

Realigning the Door

Simply replacing the faulty gearbox wouldn't have been enough.

The door was carefully adjusted and realigned so it sat correctly within the frame. This removed the unnecessary pressure from the locking mechanism and ensured all of the hooks and locking points engaged smoothly.

A professional repair should always address the underlying cause, not just replace the failed part. Door Realignment Gets Your Door Working Like New Again explains why realignment is such an important part of a lasting repair.

Fully Tested Before Completion

After reassembling everything, I thoroughly tested the door.

The results were exactly as they should be:

• The handles lifted smoothly.
• The key turned effortlessly.
• Every locking point engaged correctly.
• The door closed and locked without resistance.

I then asked the customer to try the door herself, and she was delighted with the result.

Repair, Don't Replace

This repair is a good example of why a failed lock doesn't automatically mean you need a new door or even a complete new locking mechanism. By replacing the faulty gearbox, freeing the seized hook and correctly realigning the door, the existing locking system was restored to full working order.

The customer avoided the cost of a replacement door, the lock was operating smoothly again and the door was fully secure. You Don't Need a New Door – We Can Repair It explains why repairing the original door is often the most cost-effective solution, while uPVC Door Realignment and Lock Adjustment shows how proper alignment helps prevent the same fault from returning.