I had this problem a couple of years ago, after taking out the compass as described I separated the top and base [not easy lots of small screwdrivers/wedges] .Next go to ebay and buy a folding picnic cup ,mine was pink. Remove the leaking bellows which is easy, replace with pink cup. replace top onto bottom ,a tight squeeze. Refill with liquid paraffin , available as a laxative in france. The refill is best done with a syringe. Has now lasted 2 years with no sign of a leak. Geoff