To disassemble the light just press out the cap pin with a watch band pin removal tool. It presses out just like a watch band pin. When reassembling the lighter you use a small plastic hammer to install the pin flush again. With the pin removed the off-center action spring barrel comes loose. The leak is the bottom o-ring, but you may want to rebuild the gas valve.
You needed to talk us through the fix. Also we got a great view of your thumbnail, but not so much in innards of the lighter. I have a smaller old Dunhill that is square - I am trying to figure out how to replace the flint.
Thank you for your input . what type of dunhill are you like. maybe you can ask directly via call / whatsapp +6281332210242 or e-mail bangetzbojoz@gmail.com
The Dunhill Lighters can get very dirty due to burning Butane and being used to light cigarettes and cigars. So what you get is a build up of combustion residue, much like you would see in a rifle which burns smokeless powder. So we need a solvent that will remove the combustion products but not damage the plating of the lighter, which depending on the model, can have several different finishes (plating). To clean the lighter, it is first disassembled and then cleaned with brush (Nylon Bristle Brushes with Plastic Handle) and a solvent, of which there are two popular choices. The first is lighter fluid (which I do not like) and the second is gun cleaning fluid like Rem Oil from Remington Arms. The Nylon Bristle Brushes with Plastic Handle are many times called a double-ended gun cleaning brush. Use latex gloves when using oil to clean the lighter. To clean internal surfaces that are used to seal gas you can use Rem Oil and a bore brush to remove deposits and then use IPA to remove the gun oil residue, which will evaporate and make the bore dry. The the o-rings are first lubricated before being inserted into the bore. When you clean the flint wheel striker you must make sure that it is free of debris and dry before reassemble. It is easiest to see this under a stereo microscope, the dirt can be very difficult to completely remove. The striker face should have no lubricant residue when reinstalled into the lighter. Here again you can use IPA. You could try once completely disassembled to clean the main chassis in an ultrasonic cleaner, but I am unsure of what liquid to use and at what temperature.
