BMW CARDAN INSPECTION ( DRIVE SHAFT ) DRAIN PLUG FITTED. More than a few people that have had the rubber check valve installed are saying that it fits very loose and one person said his got pushed inside the drive housing and is just laying in there. Another said they are junk and fall off, and ''mines has now fell inside the runner bungs are rubbish", ''the rubber valve they install is crap, any external pressure dislodges the valve internally leaving an open hole. There seems to be no lip on the outside to prevent it from being pushed inside. I was thinking if this is the case, perhaps some black silicone seal would be a good idea which would be easy to do. What do you think? Should we just plug it back up or use a silicone to make it stay put? Thank You!! kzbin.info/www/bejne/sJWlm5euj9x9b5o