A UPVC gearbox replacement costs £100–£180. Annual maintenance costs almost nothing. Here are five simple steps that keep a UPVC multipoint mechanism working correctly and prevent the most common causes of failure.
Why UPVC Doors Need Annual Maintenance
UPVC multipoint locking mechanisms have multiple moving metal components: hook bolts, rollers, latch plates and a central gearbox, all driven by a single handle movement. These components move every time the door is locked and unlocked. Without lubrication and basic maintenance, they wear prematurely.
A UPVC gearbox replacement costs £100–£180 and requires a locksmith visit. Annual maintenance costs the price of a can of the correct lubricant.
Step 1: Use the Correct Lubricant — Never WD-40
This is the most important maintenance point. WD-40 is a water displacer and degreaser, not a lubricant. Applied to a UPVC mechanism, it strips existing lubrication from components, attracts dust and debris, and accelerates wear. Using WD-40 on a UPVC door lock is one of the most common causes of premature mechanism failure.
Use instead:
Apply to the locking points along the door edge, the hinge pins and the handle mechanism. Once a year is sufficient for most doors.
Step 2: Keep Keep Plates Clear
The keep plates — the metal cups set into the door frame that the locking bolts engage with — accumulate dust and debris. Wipe them out annually and check they are securely fixed and correctly aligned. A misaligned keep is one of the most common causes of a door that will not lock.
Step 3: Watch the Handle
A handle becoming gradually stiffer, one that drops slightly when released, or one that requires noticeably more force than it used to, is an early warning of gearbox wear. Caught early, lubrication may solve the problem. Left until the gearbox fails completely, it requires replacement.
Step 4: Lubricate the Cylinder
The lock cylinder benefits from occasional lubrication using graphite-based lock oil or specialist lock lubricant. Apply a small amount to the key and work it in. Do not use WD-40 or household cooking oil.
Step 5: Adjust for Seasonal Changes
UPVC frames expand in summer and contract in winter. If locking becomes stiff in warm weather — or if locking points miss their keeps slightly — this is often seasonal expansion. Minor adjustments to hinges or keep plates can compensate.
If maintenance does not solve the problem, we can diagnose and repair most UPVC door issues in a single visit. Call 07984 547185 across South London.