In many older Volvo estates, the trunk only opens via central locking (if at all), because the lock housing has seized shut. A new kit lock costs about 50–70 €, but the old one can often be saved with a few hours of tinkering.

Before you can access the lock housing itself, the entire handle mechanism must be removed: Trim: Remove the tailgate interior trim plastic. Rods: Remove the locking and opening rods (secured with plastic sockets). Caution: Don't lose the small plastic collar on the open handle rod! Bolts: Open the 4 bolts/nuts (13 mm) holding the handle. Lights: Disconnect the license plate light connectors. The lights are held by plastic clips. Withdrawal: Remove the entire handle assembly from the tailgate.

The lock housing is held in the handle by a large metal socket, which lifts out by prying with a screwdriver. From the back of the lock housing, remove a smaller socket, the rod attachment part, a spacer plate, and a return spring. Tip: Take photos at each step so you remember the order and position of parts!

In reality, the lock housing is often one solid aluminum oxide lump. Soaking: Submerge the entire lock housing in a container with plenty of penetrating oil (e.g., CRC or WD-40). Let it soak for at least 15–30 minutes. Tapping: Gently tap the housing with a small hammer and move the plug back and forth in the outer shell. Do not use force, as lock metal is brittle and breaks easily. Extraction: When the plug begins to move, pull it out of the shell.

The lock housing usually contains 9 small brass wafers. The wafers are numbered, but it's easiest to keep them in exact order on a table. Remove each wafer and its small spring. Clean the wafer grooves and the wafers themselves of oxidation (e.g., with fine wet sandpaper or a brass brush). Testing: Push the key into the lock housing – all wafers must compress completely flush with the housing's body. If any binds, either it is in the wrong position or there is still dirt in the groove.

Once all parts move freely: Reassemble the lock in reverse order. Lubrication: Don't use thick vaseline, which collects dust. Use quality lock oil or synthetic gun oil. Install the handle back into the tailgate and make sure seals come between correctly to prevent water from entering the trim. Important note: If the lock is so badly oxidized that the key won't go in at all, you may have to drill the lock open or order a new one. Regular annual oiling prevents this problem from recurring.